Method of manufacturing image display panel, method of manufacturing image display device, and image display device

ABSTRACT

In the case of filling and setting the liquid powders or the particles in a plurality of cells formed by the partition walls on the substrate, the method includes the steps of: setting a nozzle at an upper portion of a container; setting the substrate, on which the partition walls are arranged, at a lower portion of the container; scattering the liquid powders or the particles dispersed in a gas from the nozzle arranged at the upper portion in the container; and filling the liquid powders or the particles in the cells on the substrate arranged at the lower portion in the container. After this filling, the method further includes: a filling step for filling a predetermined amount of the liquid powders or the particles in spaces constituting the image display cells isolated by the partition walls; a removing step for removing unnecessary liquid powders or unnecessary particles remaining on the partition walls in the filling step; a substrate stacking step for stacking the transparent substrate and the opposed substrate via the partition walls and applying a sealing agent at a peripheral portion of the substrate so as to make an atmosphere between the transparent substrate and the opposed substrate uniform; and an electrode adhering step for connecting a circuit for displaying the image to the electrode so as to form a module.

TECHNICAL FIELD

The present invention relates to a method of manufacturing an imagedisplay panel used for a reversible image display device enables torepeatedly display images accompanied by flight and movement of liquidpowders or particles utilizing Coulomb's force and so on and an imagedisplay device. Moreover, the present invention relates to a method ofmanufacturing an image display device and an image display devicemanufactured according to the above manufacturing method, which can forma module including a circuit used for an image display.

BACKGROUND ART

As an image display device substitutable for liquid crystal display(LCD), image display devices with the use of technology such as anelectrophoresis method, an electro-chromic method, a thermal method,dichroic-particles-rotary method are proposed. As for these imagedisplay device, it is conceivable as inexpensive visual display deviceof the next generation from a merit having wide field of vision close tonormal printed matter, having smaller consumption with LCD, spreadingout to a display for portable device, and an electronic paper isexpected.

Recently, electrophoresis method is proposed that micro-encapsulatedispersion liquid made up with dispersion particles and colorationsolution and dispose the liquid between faced substrates. However, inthe electrophoresis method, there is a problem that a response rate isslow by the reason of viscosity resistance because the particles migrateamong the electrophoresis solution. Further, there is a problem oflacking imaging repetition stability, because particles with highspecific gravity of titanium oxide is scattered within solution of lowspecific gravity, it is easy to subside, difficult to maintain astability of dispersion state. Even in the case of microencapsulating,cell size is diminished to a microcapsule level in order to make it hardto appear, however, an essential problem was not overcome at all.

Besides the electrophoresis method using behavior in the solution,recently, a method wherein electro-conductive particles and a chargetransport layer are installed in a part of the substrate without usingsolution is proposed. [The Imaging Society of Japan “Japan Hardcopy '99”(Jul. 21-23, 1999) Transaction Pages 249-252]However, the structurebecomes complicated because the charge transport layer and further acharge generation layer are to be arranged. In addition, it is difficultto constantly dissipate charges from the electro-conductive particles,and thus there is a drawback on the lack of stability.

In order to solve the problems mentioned above, as an image displaydevice having rapid response rate due to a dry type display, simpleconstruction, inexpensive cost and excellent stability, it is known animage display device which comprises an image display panel having oneor more image display cells isolated each other by partition walls, inwhich liquid powders composed of a solid material stably floating as adispersoid in a gas and exhibiting a high fluidity in an aerosol stateare sealed between a transparent substrate and an opposed substrate,and, in which the liquid powders, to which an electrostatic fieldproduced by a pair of electrodes having different potentials is applied,are made to fly and move so as to display an image. Moreover, it isknown an image display device utilizing normal particles in spite of theliquid powders.

However, in the dry type image display device having the constructionmentioned above, a manufacturing method is not generally established,and further it is not established a technique for sealing the particlesor the liquid powders equally and uniformly between the substrates,which is an especially important step in the manufacturing method. Here,if the step of sealing the particles or the liquid powders does notsatisfy the above conditions, there occur various problems such as acolor shading, a chipped image, a variation of image response speed dueto an unevenness of distance between the substrates, an increase ofdriving voltage for flying and moving the particles or the liquidpowders and so on.

As a method of sealing the particles (hereinafter, sometimes called aspowders) between the substrates, it is conceivable that use is made of aroll coater application method in which the powders are drew out on thesubstrate and a particle immersion method in which the particles areapplied on the substrate by floating the powders in the air by means ofagitation, air blow and so on and transferring the substrate in thefloating powders. Among them, in the roll coater application method,since it is difficult to adhere the particles to the substrate, it isliable to generate a shortage of filling amount (applying amount) of theparticles and a deviation of density. Also, in the particle immersionmethod, since it is difficult to adhere the particles to the substrate,it is liable to generate a shortage of filling amount of the particles.In addition, since the particles are not firmly secured to thesubstrate, it is liable to generate a particle flying and a particledeviation due to a shock or a wind pressure when two substrates arestacked. Therefore, both methods are not sufficient for sealing theparticles.

Moreover, in the case that a plurality of cells are formed between thesubstrates in a matrix arrangement by means of a grid spacer serving asthe partition walls and two kinds of powders are sealed in respectivecells, the particles remain on a top portion of the partition walls.Therefore, when two substrates are stacked, there is a case such thatthe particles remain in a boundary between the substrate and thepartition wall or in a boundary between the partition walls, and thusthere is a problem such that a distance between the substrates is nodemade even. In addition, there is no idea for a method of sealing theliquid powders between the substrates equally and uniformly.

Further, in the dry type image display device having the constructionmentioned above, the partition wall arrangement is normally performed bypositioning the partition walls between the transparent substrate andthe opposed substrate and applying a sealing agent to an outermostperipheral portion of the substrate. In the known manufacturing methodmentioned above, the connection between the substrate and the partitionwall has a sufficient strength in the case that a glass substrate isused as the transparent substrate and the opposed substrate, but theconnection mentioned above does not have a sufficient strength if use ismade of the other transparent substrate such as a resin substrate.Furthermore, it is not known the suitable method for forming a module ofcircuits such as a driver used for an image display.

DISCLOSURE OF INVENTION

The present invention has for its object to eliminate the drawbacksmentioned above and to provide a method of manufacturing the imagedisplay panel, which can seal the liquid powders or the particlesuniformly in a plurality of cells even when two of more kinds of theliquid powders or the particles are to be scaled. Particularly, thepresent invention has for its object to provide a method ofmanufacturing an image display panel, which can prevent liquid powdersor particles remaining in the boundary, liquid powders or particlesflying and a liquid powder layer or particle layer deviation when twosubstrates are stacked after the liquid powders or the particles areequally and uniformly arranged in a plurality of cells formed by thepartition walls arranged on the substrate.

According to the invention, a method of manufacturing an image displaypanel used for an image display device, in which liquid powders composedof a solid material stably floating as a dispersoid in a gas andexhibiting a high fluidity in an aerosol state or particles are sealedin a plurality of cells formed by partition walls between opposedsubstrates, at least one substrate being transparent, and, in which theliquid powders or the particles, to which an electrostatic field isapplied from two kinds of electrodes having different potentials, aremade to fly and move so as to display an image, is characterized inthat, in a method of manufacturing the image display panel, in which theliquid powders or the particles are sealed in the cells between thesubstrates by filling and setting the liquid powders or the particles onthe substrate to which the partition walls are arranged and then bystacking another substrate thereon, the improvement further comprises,in the case of filling and setting the liquid powders or the particlesin a plurality of cells formed by the partition walls on the substrate,the steps of: setting a nozzle at an upper portion of a container;setting the substrate, on which the partition walls are arranged, at alower portion of the container; scattering the liquid powders or theparticles dispersed in a gas from the nozzle arranged at the upperportion in the container; and filling the liquid powders or theparticles in the cells on the substrate arranged at the lower portion inthe container.

In the method of manufacturing the image display panel according to theinvention, since the method comprises, in the case of filling andsetting the liquid powders or the particles in a plurality of cellsformed by the partition walls on the substrate, the steps of: setting anozzle at an upper portion of a container; setting the substrate, onwhich the partition walls are arranged, at a lower portion of thecontainer; scattering the liquid powders or the particles dispersed in agas from the nozzle arranged at the upper portion in the container; andfilling the liquid powders or the particles in the cells on thesubstrate arranged at the lower portion in the container, it is possibleto seal the liquid powders or the particles equally and uniformly in aplurality of cells.

As one preferred embodiment of the method of manufacturing the imagedisplay panel according to the invention, in the case of filling two ormore kinds of the liquid powders or the particles having differentcolors and different characteristics, the improvement further comprisesthe steps of: filling first liquid powders or first particles in thecells on the substrate by scattering the first liquid powders or thefirst particles dispersed in the gas from the nozzle arranged at theupper portion in the container to the substrate set at the lower portionin the container; filling continuously second liquid powders or secondparticles in the cells, in which the first liquid powders or the firstparticles are filled previously, on the substrate by scattering thesecond liquid powders or the second particles dispersed in the gas fromthe nozzle arranged at the upper portion in the container to thesubstrate having the cells, in which the first liquid powders or thefirst particles are filled, arranged at the lower portion in thecontainer; and repeating the above filling steps so as to fill all kindsof the liquid powders or the particles in the cells. In the preferredembodiment mentioned above, it is possible to perform the filling of theliquid powders or the particles having different colors and havingdifferent charge characteristics into the cells more preferably.

Moreover, as an another preferred embodiment of the method ofmanufacturing the image display panel according to the invention, thescattered liquid powders or the scattered particles remaining on a topof the partition walls are removed by rolling a removing roller on thesubstrate, after filling and setting the liquid powders or the particleson the substrate to which the partition walls are arranged and beforestacking another substrate thereon. In the preferred embodimentmentioned above, since the removing roller is rolled on the substrate,it is possible to remove the liquid powders or the particles remainingon the top of the partition walls. In addition, it is possible to solvethe problems such that the liquid powders or the particles remain in aboundary between the substrate and the partition wall or in a boundarybetween the partition walls when the another substrate is stacked on theone substrate and then a distance between the substrates can not be madeeven.

As a further another preferred embodiment of the method of manufacturingthe image display panel according to the invention, there are cases:such that the removing roller has conductivity and is grounded when itis rolled on the substrate; such that a circumferential length of theremoving roller is longer than a length of the substrate from which theliquid powders or the particles are removed; such that JIS-A hardness ofthe removing roller is in a range of 40-90 degrees; and such that aconstruction material of the removing roller has a volume specificresistance of less than 1×10¹¹ Ω·cm. In each case, it is possible toperform the filling of the liquid powders or the particles into thecells preferably by optimizing the removing roller.

As a further another preferred embodiment of the method of manufacturingthe image display panel according to the invention, there is a case suchthat the partition walls are arranged on one of or both of thesubstrates. Moreover, there are cases: such that the step of removingthe scattered liquid powders or the scattered particles remaining on thetop of the partition walls by rolling the removing roller on thesubstrate is performed at every times after scattering the liquidpowders or the particles to be filled in the cells on the substrate; andsuch that the step of removing the scattered liquid powders or thescattered particles remaining on the top of the partition walls byrolling the removing roller on the substrate is performed afterscattering all the liquid powders or all the particles to be filled inthe cells on the substrate. Further, there is a case such that the stepof scattering the liquid powders or the particles is preparedcontinuously by the number of the kinds of liquid powders or the kindsof particles corresponding to the kinds of liquid powders or the kindsof particles. In each case, it is possible to perform the filling of theliquid powders or the particles into the cells preferably.

As a further another preferred embodiment of the method of manufacturingthe image display panel according to the invention, there are cases:such that a particle component constituting the liquid powders has anaverage particle diameter of 0.1-20 μm; such that a particle componentconstituting the liquid powders has a surface charge density of 5-150μC/m² in an absolute value; and such that the liquid powders filledbetween the substrates have a volume occupying rate of 5-70 vol %. Ineach case, it is possible to perform the filling of the liquid powdersmore preferably by optimizing various properties of the liquid powders.

As a further another preferred embodiment of the method of manufacturingthe image display panel according to the invention, there are cases:such that an average particle diameter of the particles is 0.1-50 μm;such that a surface charge density of the particles is 5-150 μC/m² in anabsolute value; and such that the particles filled between thesubstrates have a volume occupying rate of 5-70 vol %. In each case, itis possible to perform the filling of the particles more preferably byoptimizing various properties of the particles.

According to the invention, an image display device is characterized inthat the improvement installs the image display panel manufacturedaccording to the method of manufacturing the image display panelmentioned above.

Moreover, the present invention has for its object to eliminate thedrawbacks mentioned above and to provide a method of manufacturing animage display device and an image display device manufactured accordingto the manufacturing method mentioned above, which can further form amodule including a circuit used for an image display in a method ofmanufacturing an image display device having rapid response rate due toa dry type display, simple construction, inexpensive cost and excellentstability.

According to the invention, a method of manufacturing an image displaydevice which comprises an image display panel having one or more imagedisplay cells isolated each other by partition walls, in which two kindsof liquid powders composed of a solid material stably floating as adispersoid in a gas and exhibiting a high fluidity in an aerosol state,having a white color and a black color and having different chargecharacteristics, or, two kinds of particles having a white color and ablack color and having different charge characteristics, are sealedbetween a transparent substrate and an opposed substrate, and, in whichthe liquid powders or the particles, to which an electrostatic fieldproduced by a pair of electrodes having different potentials is applied,are made to fly and move so as to display a monotone image, ischaracterized in that the improvement further comprises: a filling stepfor filling a predetermined amount of the liquid powders or theparticles in spaces constituting the image display cells isolated by thepartition walls; a removing step for removing unnecessary liquid powdersor unnecessary particles remaining on the partition walls in the fillingstep; a substrate stacking step for stacking the transparent substrateand the opposed substrate via the partition walls and applying a sealingagent at a peripheral portion of the substrate so as to make anatmosphere between the transparent substrate and the opposed substrateuniform; and an electrode adhering step for connecting a circuit fordisplaying the image to the electrode so as to form a module (firstembodiment).

Moreover, according to the invention, a method of manufacturing an imagedisplay device which comprises an image display panel having one or moreimage display cells isolated each other by partition walls, in which twokinds of liquid powders composed of a solid material stably floating asa dispersoid in a gas and exhibiting a high fluidity in an aerosolstate, having a predetermined color other than white color and a blackcolor and having different charge characteristics, or, two kinds ofparticles having a predetermined color other than white color and ablack color and having different charge characteristics, are sealedbetween a transparent substrate and an opposed substrate, and, in whichthe liquid powders or the particles, to which an electrostatic fieldproduced by a pair of electrodes having different potentials is applied,are made to fly and move so as to display a color image, ischaracterized in that the improvement further comprises: a filling stepfor filling a predetermined amount of the liquid powders or theparticles in spaces constituting the image display cells isolated by thepartition walls; a removing step for removing unnecessary liquid powdersor unnecessary particles remaining on the partition walls in the fillingstep; a substrate stacking step for stacking the transparent substrateand the opposed substrate via the partition walls and applying a sealingagent at a peripheral portion of the substrate so as to make anatmosphere between the transparent substrate and the opposed substrateuniform; and an electrode adhering step for connecting a circuit fordisplaying the image to the electrode so as to form a module (secondembodiment).

Further, according to the invention, a method of manufacturing an imagedisplay device which comprises an image display panel having one or moreimage display cells isolated each other by partition walls, in which twokinds of liquid powders composed of a solid material stably floating asa dispersoid in a gas and exhibiting a high fluidity in an aerosolstate, having a white color and a black color and having differentcharge characteristics, or, two kinds of particles having a white colorand a black color and having different charge characteristics, aresealed between a transparent substrate and an opposed substrate, and, inwhich the liquid powders or the particles, to which an electrostaticfield produced by a pair of electrodes having different potentials isapplied, are made to fly and move so as to display a color image via acolor filter provided to the transparent substrate constituting a frontpanel, is characterized in that the improvement further comprises: afilling step for filling a predetermined amount of the liquid powders orthe particles in spaces constituting the image display cells isolated bythe partition walls; a removing step for removing unnecessary liquidpowders or unnecessary particles remaining on the partition walls in thefilling step; a substrate stacking step for stacking the transparentsubstrate and the opposed substrate via the partition walls and applyinga sealing agent at a peripheral portion of the substrate so as to makean atmosphere between the transparent substrate and the opposedsubstrate uniform; and an electrode adhering step for connecting acircuit for displaying the image to the electrode so as to form a module(third embodiment).

As another preferred embodiments of the method of manufacturing theimage display device according to the invention (first to thirdembodiments), there are cases: such that an apparent volume in a maximumfloating state of the liquid powders is two times or more than that innone floating state; such that a time change of the apparent volume ofthe liquid powders satisfies the following formula: V₁₀/V₅>0.8; here, V₅indicates the apparent volume (cm³) of the liquid powders after 5minutes from the maximum floating state; and V₁₀ indicates the apparentvolume (cm³) of the liquid powders after 10 minutes from the maximumfloating state; and such that an average particle diameter d(0.5) of aparticle component constituting the liquid powders is 0.1-20 μm, In eachcase, it is possible to perform the method of manufacturing the imagedisplay device according to the invention more preferably.

Moreover, as further another preferred embodiments of the method ofmanufacturing the image display device according to the invention (firstto third embodiments), there are cases: such that an average particlediameter of the particles is 0.1-50 μm; such that a difference betweensurface charge densities of the two kinds of particles measured byutilizing same carrier and in accordance with a blow-off method is 5μC/m²-150 μC/m² in an absolute value; and such that the particles areparticles in which the maximum surface potential, in the case that thesurface of particles is charged by a generation of Corona dischargecaused by applying a voltage of 8 KV to a Corona discharge devicedeployed at a distance of 1 mm from the surface, is 300 V or greater at0.3 second after the discharge. In each case, it is possible to performthe method of manufacturing the image display device according to theinvention more preferably.

Further, according to the invention, an image display device ischaracterized in that the improvement is manufactured according to themethod of manufacturing the image display device mentioned above.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view showing one embodiment of a display method inan image display panel, which is manufactured by a method ofmanufacturing an image display panel according to the invention.

FIG. 2 is a schematic view illustrating another embodiment of a displaymethod in an image display panel, which is manufactured by a method ofmanufacturing an image display panel according to the invention.

FIG. 3 is a schematic view depicting one embodiment of a panel structurein an image display panel, which is manufactured by a method ofmanufacturing an image display panel according to the invention.

FIGS. 4 a-4 c are schematic views respectively showing one embodiment ofa display element in an image display device, which is manufactured by amethod of manufacturing an image display device according to theinvention, and its display operation theory.

FIG. 5 is a schematic view illustrating another embodiment of a displayelement in an image display device, which is manufactured by a method ofmanufacturing an image display device according to the invention,wherein a display electrode is provided on a transparent substrate andan opposed electrode is provided on an opposed substrate.

FIG. 6 is a schematic view depicting one embodiment of a method offiling liquid powders or particles in a method of manufacturing an imagedisplay panel according to the invention.

FIG. 7 is a schematic view showing another embodiment of a method offilling liquid powders or particles in a method of manufacturing animage display panel according to the invention.

FIG. 8 is a schematic view illustrating one embodiment of a removal ofliquid powders or particles by utilizing a removal roller in a method ofmanufacturing an image display panel according to the invention.

FIGS. 9 a-9 d are schematic views depicting another embodiment of aremoval of liquid powders or particles by utilizing a removing meanssuch as a removal roller in a method of manufacturing an image displaypanel according to the invention.

FIG. 10 is a schematic view showing one embodiment wherein a fillingstep of liquid powders or particles is performed continuously in amethod of manufacturing an image display panel according to theinvention.

FIG. 11 is a schematic view illustrating one embodiment of an apparatusfor measuring a surface potential of a removal roller utilizing in amethod of manufacturing an image display panel according to theinvention.

FIG. 12 is a schematic view depicting a shape of a display cell formedby partition walls.

FIG. 13 is a schematic view explaining one embodiment of a filling stepin a method of manufacturing an image display device according to theinvention.

FIGS. 14 a and 14 b are schematic views respectively explaining oneembodiment of a removing step in a method of manufacturing an imagedisplay device according to the invention.

FIGS. 15 a-15 c are schematic views respectively explaining oneembodiment of a substrate stacking step in a method of manufacturing animage display device according to the invention.

FIGS. 16 a-16 c are schematic views respectively explaining oneembodiment of an electrode adhering step in a method of manufacturing animage display device according to the invention.

FIG. 17 is a schematic view showing one structure of a mono-chrome imagedisplay panel according to a first embodiment in a method ofmanufacturing an image display device according to the invention.

FIGS. 18 a and 18 b are schematic views respectively explaining oneembodiment of a color filter stacking step in a method of manufacturingan image display device according to the invention.

FIG. 19 is a schematic view showing one structure of a color imagedisplay panel according to a second embodiment in a method ofmanufacturing an image display device according to the invention.

FIGS. 20 a and 20 b are schematic views respectively illustrating onestructure of a color image display panel according to a third embodimentin a method of manufacturing an image display device according to theinvention.

FIG. 21 is a schematic view explaining a method of measuring a volumespecific resistance.

BEST MODE FOR CARRYING OUT THE INVENTION

A method of manufacturing an image display panel according to theinvention can be applied to both of display methods: one method(referred to FIG. 1) wherein an image display is performed by movingliquid powders 5, 6 having different colors and two or more kinds in avertical direction with respect to substrates 1, 2; and the other method(referred to FIG. 2) wherein an image display is performed by moving theliquid powders 5 having one color and one kind in a parallel directionwith respect to the substrates 1, 2. Moreover, one embodiment of a panelstructure for display is shown in FIG. 3. As shown in FIG. 3 by oneexample, a feature of the image display panel according to the inventionis a method of filling predetermined liquid powders 5, 6 into a cell 9formed by partition walls 4 having for example a grid shape between thesubstrates 1, 2. It should be noted that, in the image display panelsshown in FIGS. 1-3, the same effects can be obtained even if the liquidpowders 5, 6 are substituted by particles 5, 6.

Then, a device, which is a target of a method of manufacturing an imagedisplay device according to the invention, will be explained. FIGS. 4 ato 4 c are schematic views respectively showing one embodiment of theimage display element of the image display panel used for the imagedisplay device according to the invention and its display drivingmethod. In the embodiments shown in FIGS. 4 a to 4 c, numeral 1 is atransparent substrate, numeral 2 is an opposed substrate, numeral 3 is adisplay electrode, numeral 4 is an opposed electrode, numeral 5 isnegatively chargeable liquid powders, numeral 6 is positively chargeableliquid powders, numeral 7 is a partition wall and numeral 8 is aninsulation member.

FIG. 4 a shows a state such that the negatively chargeable liquidpowders 5 and the positively chargeable liquid powders 6, which arecomposed of a solid material stably floating as a dispersoid in a gasand exhibiting a high fluidity in an aerosol state, are arranged betweenopposed substrates (transparent substrate 1 and opposed substrate 2).Under such a state, when a voltage is applied in such a manner that aside of the display electrode 3 becomes low potential and a side of theopposed electrode 4 becomes high potential, as shown in FIG. 4 b, thepositively chargeable liquid powders 6 fly and move to the side of thedisplay electrode 3 and the negatively chargeable liquid powders 5 flyand move to the side of the opposed electrode 4 by means of Coulomb'sforce. In this case, a display face viewed from a side of thetransparent substrate 1 looks like a color of the positively chargeableliquid powders 6. Next, when a voltage is applied in such a manner thatthe side of the display electrode 3 becomes high potential and the sideof the opposed electrode 4 becomes low potential by reversingpotentials, as shown in FIG. 4 c, the negatively chargeable liquidpowders 5 fly to move to the side of the display electrode 3 and thepositively chargeable liquid powders 6 fly to move to the side of theopposed electrode 4 by means of Coulomb's force. In this case, thedisplay face viewed from the side of the transparent substrate 1 lookslike a color of the negatively chargeable liquid powders 5.

The display states shown in FIGS. 4 b and 4 c are repeatedly changeableonly by reversing the potentials of a power source, and thus it ispossible to change colors on the display face reversibly by reversingthe potentials of the power source as mentioned above. The colors of theliquid powders can be arbitrarily selected. For example, when thenegatively chargeable liquid powders 5 are white color and thepositively chargeable liquid powders 6 are black color, or, when thenegatively chargeable liquid powders 5 are black color and thepositively chargeable liquid powders 5 are white color, a reversibleimage display between white color and black color can be performed. Inthis method, since the liquid powders are once adhered to the electrodeby means of an imaging force, a display image can be maintained for along time after a voltage apply is stopped, thereby showing an excellentmemory property.

In the embodiment shown in FIG. 4, two kinds of electrodes havingdifferent potentials i.e. the display electrode 3 and the opposedelectrode 4 are provided to a side of the opposed substrate 2 opposed tothe transparent substrate 1. As an another method of providing theelectrodes, as shown in FIG. 5, there is a method for providing thedisplay electrode 3 on the transparent substrate 1 and the opposedelectrode 4 on the opposed substrate 2. In this case, it is necessary touse a transparent electrode as the display electrode 3. In theembodiment shown in FIG. 4, since it is possible to use an opaqueelectrode as both of the display electrode 3 and the opposed electrode4, it is possible to use a metal electrode having an inexpensive costand a low resistance such as copper, aluminum and so on. The appliedouter voltage may be superimposed with a direct current or an alternatecurrent. It is preferred to form a coat layer having an insulationproperty to respective electrodes so as not to leak a charge of thecharged liquid powders. As the coat layer mentioned above, it isparticularly preferred to use a positively chargeable resin for thenegatively chargeable liquid powders and a negatively chargeable resinfor the positively chargeable liquid powders, since a charge of liquidpowders become difficult to leak.

The feature of the method of manufacturing the image display deviceaccording to the invention is to combine a filling step of liquidpowders, a removing step of liquid powders, a substrate stacking stepand an electrode adhering step when manufacturing the image displaydevice having the construction mentioned above. It should be noted that,in the image display device shown in FIGS. 4 and 5, the same effects canbe obtained even if the liquid powders 5, 6 are substituted by theparticles 5, 6.

(As to the method of manufacturing the image display panel)

Hereinafter, one example of a method of filling the liquid powders,which is a feature of the method of manufacturing the image displaydevice according to the invention, will be explained. It should be notedthat the following explanation is made to the liquid powders as oneexample but the same filling method of the liquid powders mentionedbelow can be applied to the particles. Moreover, details of respectiveconstruction members will be explained later.

As shown in FIG. 6, a nozzle 12 is arranged to an upper portion in acontainer 11, and the substrate 1, on which partition walls 7 arearranged so as to form a cell 9, is arranged to a lower portion in thecontainer 11. In this case, the substrate 1 is set in such a manner thatan opening of the cell 9 is opposed to the nozzle 12. Here, thepartition wall is a member, which constitutes the partition walls 7after the image display device is accomplished, and thus they areindicated as the partition walls 7. Under such a condition, first liquidpowders 5 being dispersed in a gas are scattered in the container 11from the nozzle 12 arranged at the upper portion of the container 11,and then the first liquid powders 5 are filled in the cell 9 on thesubstrate 1 arranged at the lower portion in the container 11.

Further, FIG. 7 shows a method of filling second liquid powders 6. Asshown in FIG. 7, the substrate 1, in which the first liquid powders 5are filled in the cell 9, is arranged at the lower portion in thecontainer 11, and the second liquid powders 6 being dispersed in a gasare scattered from the nozzle 12 provided at the upper portion in thecontainer 11, so that the second liquid powders 6 are filled in the cell9 on the substrate 1, in which the first liquid powders 5 arepreliminarily filled. If the steps mentioned above is repeated by thenumber of kinds of the liquid powders, the same filling step of theliquid powders 5, 6 into the cell 9 can be performed according to theinvention even when the kinds of the liquid powders are three or more.

Both in the example shown in FIG. 6 and in the example shown in FIG. 7,after the steps mentioned above are finished, another kind of substrate(not shown) is adhered to the partition walls 7, so that it is possibleto manufacture the image display panel according to the invention.

In the embodiment mentioned above, there is a case such that the liquidpowders 5, 6 remain on a top of the partition wall 7. In such a case, itis preferred to remove the liquid powders 5, 6 from the top of thepartition wall 7 by rolling a conductive removing roller 21, which isgrounded, on the partition walls 7 of the substrate 1, as shown in FIG.8 before the another substrate is stacked. In this embodiment, since theliquid powders 5, 6 remaining on the top of the partition wall 7 aremoved and adhered to the removing roller 21, it is possible to removethe liquid powders 5, 6 from the top of the partition wall 7. Moreover,as mentioned above, it is preferred to use the conductive removingroller 22, which is grounded. However, in order to remove the liquidpowders 5, 6, as shown in FIG. 9 a, use is made of the removing roller21, which is not grounded, and the removing roller 21 is rolled on thepartition walls 7 of the substrate 1, so that it is possible to removethe liquid powders 5, 6. In this case, it is preferred that, accordingto need, use is further made of a charge removing blower and the liquidpowders 5, 6 remaining on the top of the partition wall 7 are furtherremoved by using the charge removing blower.

Further, in order to remove the liquid powders 5, 6, it is possible toremove the unnecessary liquid powders 5, 6 on the partition wall 7 bysliding a plate member 51 such as a blade on the substrate 1 with afriction as shown in FIG. 9 b and also it is possible to remove theunnecessary liquid powders 5, 6 on the partition wall 7 by oscillating apress plate 52 with a movement in forward and backward directions, amovement in left and right directions and a rotation under such acondition that the press plate 52 is pressed to the substrate 1 as shownin FIG. 9 c. Furthermore, as shown in FIG. 9 d, it is possible to removethe unnecessary liquid powders 5, 6 on the partition wall 7 by pressingan adhesion sheet 53 to the substrate 1. In FIG. 9 d, numeral 54 is anadhesion sheet wind-off roller, numeral 55 is a charge remover, numeral56 is a press roller, numeral 57 is an adhesion sheet rewind roller,numeral 58 is a transfer belt and numeral 59 is a press roller or adrive roller.

FIG. 10 is a schematic view showing one embodiment wherein the firstliquid powder filling step and the second liquid powder filling stepmentioned above are performed continuously. In the embodiment shown inFIG. 10, a continuous line is formed by arranging a plurality ofsubstrates 1 on a transfer belt (not shown) in such a manner that thecell 9 is faced upward. Then, in a first liquid powder filling zone, thefirst liquid powders 5 are filled in the cell 9 formed by the partitionwalls 7 on the substrate, as is the same as the embodiment shown in FIG.6. In a second liquid powder filling zone, the second liquid powders 6are filled in the cell 9 formed by the partition walls 7 on thesubstrate 1, as is the same as the embodiment shown in FIG. 7. In aliquid powder removing zone, the liquid powders 5, 6 remaining on thetop of the partition wall 7 are removed, as is the same as theembodiments shown in FIGS. 8 and 9. In a substrate stacking zone, thesubstrate 2 is adhered to the partition walls 7 under such a conditionthat the liquid powders 5 and the liquid powders 6 are filled in thecell 9. In a final zone, an image display panel 22 according to theinvention is obtained.

Then, the removing roller 21 will be explained.

The removing roller 21 has JIS-A hardness in a range of 40-90° and ismade of a conductive material having a volume specific resistance in arange of less than 1×10¹¹ Ω·cm. In the case such that the liquid powders5, 6 remaining on the top of the partition wall 7 are removed, it ispreferred that the removing roller 21 is grounded. If JIS-A hardness ofthe removing roller 21 exceeds 90°, the removing roller 21 is pressed tothe substrate 1 too hard, and thus the liquid powders 5, 6 remaining onthe top of the partition wall 7 are cut into the top of the partitionwall 7, so that a removing step, wherein the liquid powders 5, 6 aremoved to the removing roller 21, is not performed preferably. If JIS-Ahardness is less than 40°, a deformation of the removing roller 21 istoo large, and thus the liquid powders 5, 6 filled in the cell 9 aresometimes moved to the removing roller 21, so that it is not preferred.If the volume specific resistance of the removing roller 21 exceeds1×10¹¹ Ω·cm, the removing roller 21 becomes chargeable even when it isgrounded, and thus the liquid powders 5, 6 filled in the cell 9 aresometimes moved to the removing roller 21 by means of the chargedremoving roller 21.

In the case of using the removing roller 21, it is preferred that theremoving roller 21 is grounded. If the removing roller 21 is notgrounded, the removing roller 21 itself becomes chargeable and is liableto suck fine particles. Therefore, there is a case such that theremoving roller 21 removes not only the liquid powders 5, 6 remaining onthe top of the partition wall 7 to be removed but also the liquidpowders 5, 6 filling in the cell 9. Moreover, it is preferred that anouter circumferential length of the removing roller 21 is longer than alength of the substrate 1 wherein the liquid powders 5, 6 are remainingon the top of the partition wall. If it is not longer that the length ofthe substrate 1, a portion of the removing roller 21 to which the liquidpowders 5, 6 are adhered is again rolling on the substrate 1 wherein theliquid powders 5, 6 are remaining on the top of the partition wall 7,the liquid powder removing step can not be performed preferably.

As a material used for the removing roller 21, use is made of aconductive material having properties mentioned above, and generally useis made of a material used for a conductive roller utilized in OA(office automation) equipments such as printer and so on preferably. Asone example of such materials, there are: resins such as urethane rein,acrylate resin, polyester resin, urethane modified acrylate resin,silicone resin, nylon resin, epoxy resin, styrene resin, butyral resin,vinylidene chloride resin, melamine resin, phenol resin, fluorocarbonresin, acrylic urethane resin, acrylic urethane silicone resin, acrylicurethane fluorocarbon resin; rubbers such as urethane rubber, siliconerubber, fluorocarbon rubber, ethylene propylene rubber, butadienerubber, styrene butadiene rubber, natural rubber, nitrite rubber; and acomposite material wherein conductive agents are added to the resins orrubbers mentioned above and a volume specific resistance is controlledin a range of less than 1×10¹¹ Ω·cm.

As a measure of easily chargeable property and easily charge leakproperty of the removing roller 21, there is a charge-up property. Inthe case such that use is made of a roller having high charge-upproperty as the removing roller 21 used for removing the liquid powders5, 6 remaining on the top of the partition wall 7, since a surface ofthe roller is easily chargeable and a charge is not easily leaked, itbecomes a state such that a surface charge is easily maintained. Undersuch a state, if the roller is approached to the panel in which chargedliquid powders are filled, there is a drawback such that a charge stateis uneven because a charge of the charged liquid powders is discharged.Even if a charge is not discharged, there is a drawback such that theliquid powders in the panel are adhered to the roller because a chargeof the liquid powders is attracted to the roller. In this manner, thecharge state of the liquid powders becomes uneven. Therefore, there is apreferable range for the charge-up property.

In the present invention, from the viewpoint mentioned above, asdisclosed in the applicant's Japanese Patent Laid-open Publication No.2000-206777, it is preferred that: the removing roller is formed byarranging a semiconductor elastic layer around a periphery of aconductive shaft and further arranging a semiconductor elastic coatinglayer on its outermost periphery; and the maximum surface potential, inthe case that the surface is charged by a generation of Corona dischargecaused by applying a voltage of 8 KV to a Corona discharge devicedeployed at a distance of 1 mm from the surface, is 90 V or less at 0.35second after the discharge. Moreover, as disclosed in the applicant'sJapanese Patent Laid-open Publication No. 2000-206778, it is preferredthat: the removing roller is formed by arranging a semiconductor elasticlayer around a periphery of a conductive shaft; and the surfacepotential attenuation rate, in the case that the surface is charged by ageneration of Corona discharge caused by applying a voltage of 8 KV to aCorona discharge device deployed at a distance of 1 mm from the surface,is 0.1 (V/sec) or greater in a absolute value at 0.1-0.2 second afterthe charge applying operation.

Additionally, the charge applying operation to the removing roller 21and the surface potential measurement are performed by means of aninstrument for example as shown in FIG. 11. That is, both end portionsof a roll shaft 25 of the removing roller 21 are held with chuck 26, anda compact scorotron discharger 27 and a surface potential meter 28 arespaced with predetermined interval to form a measurement unit. Themeasurement unit is facedly deployed with a distance of 1 mm from thesurface of the removing roller 21, and by moving the measurement unit27, 28 from one end portion of the removing roller 21 to the other endportion with an uniform speed, with the state that the removing roller21 remains stopping and while giving surface charge, a method ofmeasuring its surface potential is preferably adopted.

As to the First Embodiment of the Method of Manufacturing the ImageDisplay Device

Hereinafter, respective steps, which are features of the firstembodiment of the method of manufacturing the image display deviceaccording to the invention, will be explained. It should be noted thatthe explanation is made to the liquid powders as one example in theexplanation mentioned below, but it is possible to utilize the samefilling steps for the liquid powders as it is with respect to the methodof filling the particles if the liquid powders are exchanged to theparticles.

The features on the first embodiment of the method of manufacturing theimage display device according to the invention are to combine a liquidpowder filling step, a liquid powder removing step, a substrate stackingstep and an electrode adhering step, when manufacturing the imagedisplay device having the construction mentioned above. It should benoted that, in the embodiments mentioned below, the explanation is madeto a monotone display of PDA (Personal Digital Assistant) as one exampleof the image display device wherein an electrode width corresponding toone pixel is 300 μm, an electrode interval is 50 μm, an interval betweenthe transparent substrate 1 and the opposed substrate 2 is 50 μm and anopening rate is 75%. Moreover, details of respective constructionmembers will be explained later.

(1) As to the filling step of the liquid powders:

FIG. 13 is a schematic view explaining one embodiment of the fillingstep of the liquid powders. In the embodiment shown in FIG. 13, apredetermined amount of black liquid powders 5 and a predeterminedamount of white liquid powders 6 are orderly filled from a fillingapparatus 11 in a space constituting the image display element formed bythe partition walls 7 arranged on the opposed substrate 2. As the methodof filling the liquid powders, use is made of a method for scatteringthe liquid powders 5, 6 to the opposed substrate 2 by utilizing gravityor air flow or a method for flying the liquid powders 5, 6 by utilizingan electrostatic charge. At that time, if necessary, the liquid powders5, 6 are forcedly charged so as to be a mono-disperse state and arescattered for the purpose of evenly scattering by eliminating anagglutination of the liquid powders. Moreover, there is a case such thatan electric field is applied to the opposed substrate 2 for the purposeof effectively scattering the liquid powders 5, 6 to the opposedsubstrate 2.

In the present invention, when two or more kinds of different colors anddifferent charge characteristics are filled in a predetermined position,a separately filling is preferably performed. However, according to acombination of the utilized two or more kinds of liquid powders orparticles, it is possible to fill the liquid powders or the particlesafter preliminarily mixing them. In this case, since the filling step isfinished only by one step, there is a merit such that the filling stepis shortened. However, when use is made of two or more kinds of liquidpowders or particles having different colors and different chargecharacteristics as mentioned above, the mixture is liable to be uneven,and thus it is necessary to use an even mixture as far as possible.

(2) As to the removing step of the unnecessary liquid powders:

FIGS. 14 a and 14 b are schematic views respectively explaining oneembodiment of the removing step of the liquid powders. After the fillingstep of the liquid powders is finished, in the case such that thetransparent substrate 1 and the opposed substrate 2 are stacked, asshown in FIG. 14 b, it is necessary to remove the unnecessary liquidpowders 5, 6 remaining on the partition wall 7 as shown in FIG. 14 a. Ifthe unnecessary liquid powders 5, 6 remain, a distance between theelectrode 3 and the electrode 4 is made to be uneven when the substratesare stacked. Therefore, a driving voltage becomes different from adesign value, and thus it is not possible to achieve desired displaycharacteristics. As a method of removing the unnecessary liquid powders5, 6 remaining on the partition wall 7, use is made of a method forremoving them by utilizing an adhesive roll, a method for removing theunnecessary liquid powders by blowing them away by means of an air flow.As the another method, as shown in FIGS. 9 b, 9 c and 9 d, it ispossible to remove the unnecessary liquid powders 5, 6 on the partitionwall 7 by sliding a plate member such as a blade on the substrate 1 witha friction, or, it is possible to remove the unnecessary liquid powders5, 6 on the partition wall 7 by pressing a sheet-like member or afilm-like member to the substrate 1. Moreover, if use is made of a stepwherein the liquid powders 5, 6 are not adhered to the partition wall 7selectively, it is not necessary to perform the removing step of theliquid powders 5, 6 on the partition wall 7.

(3) As to the substrate stacking step:

FIGS. 15 a-15 c are schematic views respectively explaining oneembodiment of the substrate stacking step. In this embodiment, apositioning alignment is performed by utilizing the opposed substrate 2and the transparent substrate 1 to which a mark for positioning ispreliminarily arranged. In this case, for the purpose of improvingdurability and reliability as the display, an adhesive 32 is arranged ona tip portion of the partition wall 7 as shown in FIG. 15 a, and aconnection between the partition wall 7 and the transparent substrate 1is performed through the adhesive 32. As a method of arranging theadhesive 32, use is made of a method for screen-printing a thermosettingor UV hardening adhesive, a method for arranging an adhesive layer forsealing on an overall surface of the transparent substrate 1, or, amethod for scattering the liquid powders having adhesion properties andsealing by heat and pressure.

Further, for the purpose of preventing an inclusion of component, whichaffects the display, such as external moisture content, a scaling agentis applied around an outermost peripheral portion of the substrate so asto seal a space between the substrates. As a method of applying thesealing agent, use is made of a method wherein a sealing agent 34 isapplied to the outermost peripheral portion by means of a sealing agentapplying device 33 as shown in FIG. 15 b after the adhesive 12 isarranged on a tip portion of the partition wall 7 as mentioned above,and then as shown in FIG. 15 c, the transparent substrate 1 and theopposed substrate 2 are positioned by utilizing an position aligningdevice not shown and are stacked. It should be noted that, if use ismade of a transparent substrate with a color filter as the transparentsubstrate 1 mentioned above, it is possible to obtain an image displaypanel for a color display utilizing the color filter.

(4) As to the electrode adhering step:

FIGS. 16 a-16 c are schematic views respectively explaining oneembodiment of the electrode adhering step. In this embodiment, for thepurpose of transmitting a signal for image display to an image displaypanel 35 so as to obtain an image display device wherein the imagedisplay panel 35 (display) is formed as a module, the electrodes 3, 4 ofthe image display plate 35 and a driving circuit 36 are connected. Atfirst, as shown in FIG. 16 a, a stripe electrode with the rib is formedon an outer surface of the transparent substrate 1 being a front planeas the display electrode 3. Then, as shown in FIG. 16 b, a stripeelectrode with the rib is formed on an outer surface of the opposedsubstrate 2 being a rear plane as the opposed electrode 4. After that,as shown in FIG. 16 c, the electrodes 3, 4 of the image display panel 35and the external driving circuit 36 formed by ACF (AnisotropicConductive Film) are connected, and then the image display device formedas a module is obtained.

As a method of connecting the electrodes, use is made of a method fordirectly installing IC on the substrate by utilizing an adhesive, amethod of installing a flexible printed board by utilizing an adhesiveand so on. As the adhesive, use is made of an anisotropic conductivepaste, and an adhesive in which the conductive particles are notscattered, except for an anisotropic conductive film made of an adhesivehaving an anisotropic property in which the conductive particles arescattered therein as mentioned above.

According to the steps mentioned above, the image display panel 35 isformed as a module and the image display device is manufactured. FIG. 17is a schematic view showing one embodiment of the image display panel 24according to the invention, which performs a monotone display. In theembodiment mentioned above, the display electrode 3 and the opposedelectrode 4 are respectively arranged on outer surfaces of theintegrated image display panel 35. However, as shown in FIGS. 4 and 5,it is possible to arrange the display electrode 3 and the opposedelectrode 4 to inner portions of the image display panel 35. In thiscase, prior to integrate the image display panel 35, the displayelectrode 3 and the opposed electrode 4 may be arranged. Moreover, thepartition walls 7 are arranged only to the opposed substrate 2. However,they are arranged to both of the transparent substrate 1 and the opposedsubstrate 2 and the image display panel 35 is integrated by connectingthe partition walls with each other.

As to the Second and Third Embodiments of the Method of Manufacturingthe Image Display Device

Hereinafter, respective steps, which are features of the second andthird embodiments of the method of manufacturing the image displaydevice according to the invention, will be explained. It should be notedthat the explanation is made to the liquid powders as one example in theexplanation mentioned below, but it is possible to utilize the samefilling steps for the liquid powders as it is with respect to the methodof filling the particles if the liquid powders are exchanged to theparticles.

The features on the second embodiment of the method of manufacturing theimage display device according to the invention, in which the colordisplay is performed by utilizing a predetermined color liquid powdersand a black liquid powders, are to combine a liquid powder filling step,a liquid powder removing step, a substrate stacking step and anelectrode adhering step, when manufacturing the image display devicehaving the construction mentioned above. Moreover, the features on thethird embodiment of the method of manufacturing the image display deviceaccording to the invention, in which the color display is performedthrough the color filter by utilizing white color liquid powders andblack liquid powders, are to combine a liquid powder filling step, aliquid powder removing step, a substrate stacking step, a color filterstacking step (this step is not necessary when the transparent substrateutilized as the front panel has the color filter) and an electrodeadhering step, when manufacturing the image display device having theconstruction mentioned above. Hereinafter, one embodiment of respectivesteps will be explained in detail. It should be noted that, in theembodiments mentioned below, the explanation is made to a monotonedisplay of PDA (Personal Digital Assistant) as one example of the imagedisplay device wherein an electrode width corresponding to one pixel is300 μm, an electrode interval is 50 μm, an interval between thetransparent substrate 1 and the opposed substrate 2 is 50 μm and anopening rate is 75%. Moreover, details of respective constructionmembers will be explained later. Further, among the steps of the firstembodiment explained by using FIGS. 13-16, the same figures are used forthe overlapped steps.

(1) As to the filling step of the liquid powders:

FIG. 13 is a schematic view explaining one embodiment of the fillingstep of the liquid powders. In the embodiment shown in FIG. 13, apredetermined amount of black liquid powders 5 and a predeterminedamount of the liquid powders 6 having given color other than white inthe second embodiment or a predetermined amount of white liquid powders6 in the third embodiment wherein the color filter is used are orderlyfilled from a filling apparatus 11 in a space constituting the imagedisplay element formed by the partition walls 7 arranged on the opposedsubstrate 2. As the method of filling the liquid powders, use is made ofa method for scattering the liquid powders 5, 6 to the opposed substrate2 by utilizing gravity or air flow or a method for flying the liquidpowders 5, 6 by utilizing an electrostatic charge. At that time, ifnecessary, the liquid powders 5, 6 are forcedly charged so as to be amono-disperse state and are scattered for the purpose of evenlyscattering by eliminating an agglutination of the liquid powders.Moreover, there is a case such that an electric field is applied to theopposed substrate 2 for the purpose of effectively scattering the liquidpowders 5, 6 to the opposed substrate 2.

As a coloring method, as mentioned above, use is made of a method forutilizing the color liquid powders (the second embodiment), or, a methodfor utilizing the color filter (the third embodiment). In the case suchthat the color filter is used, it is possible to perform a color imagedisplay by filling the white and black liquid powders as mentionedabove. On the other hand, in the case such that the color liquid powdersare used, it is necessary to fill the liquid powders having variouscolors selectively into a space constituting the image display element(hereinafter, sometimes called as a cell). As a method of filling theliquid powders, use is made of a method wherein a mask is arranged at anupper portion of the cell and the liquid powders are selectively filledin a desired cell, or, a method wherein an electrostatic field showingthe reverse charge with respect to a charge of the liquid powders to bescattered is applied to the cell, the liquid powders are selectivelyfilled while an electrostatic filed showing the same charge with respectto the charge of the liquid powders to be scattered is applied to theother cells, so that the liquid powders are not selectively filled inthe other cells.

In the present invention, when two or more kinds of different colors anddifferent charge characteristics are filled in a predetermined position,a separately filling is preferably performed. However, according to acombination of the utilized two or more kinds of liquid powders orparticles, it is possible to fill the liquid powders or the particlesafter preliminarily mixing them. However, even in this case, since colorcombinations of the liquid powders to be filled in a predetermined cellare different respectively, it is necessary to perform the filling stepby at least three times. Therefore, in the case that the filling stepfor the black liquid powders is separately performed, there is not muchmerit as compared with a case such that it is necessary to perform thefilling step by at least four times.

(2) As to the removing step of the unnecessary liquid powders;

FIGS. 14 a and 14 b are schematic views respectively explaining oneembodiment of the removing step of the liquid powders. After the fillingstep of the liquid powders is finished, in the case such that thetransparent substrate 1 and the opposed substrate 2 are stacked, asshown in FIG. 14 b, it is necessary to remove the unnecessary liquidpowders 5, 6 remaining on the partition wall 7 as shown in FIG. 14 a. Ifthe unnecessary liquid powders 5, 6 remain, a distance between theelectrode 3 and the electrode 4 is made to be uneven when the substratesare stacked. Therefore, a driving voltage becomes different from adesign value, and thus it is not possible to achieve desired displaycharacteristics. As a method of removing the unnecessary liquid powders5, 6 remaining on the partition wall 7, use is made of a method forremoving them by utilizing an adhesive roll, a method for removing theunnecessary liquid powders by blowing them away by means of an air flow.As the another method, as shown in FIGS. 9 b, 9 c and 9 d, it ispossible to remove the unnecessary liquid powders 5, 6 on the partitionwall 7 by sliding a plate member such as a blade on the substrate 1 witha friction, or, it is possible to remove the unnecessary liquid powders5, 6 on the partition wall 7 by pressing a sheet-like member or afilm-like member to the substrate 1. Moreover, if use is made of a stepwherein the liquid powders 5, 6 are not adhered to the partition wall 7selectively, it is not necessary to perform the removing step of theliquid powders 5, 6 on the partition wall 7.

(3) As to the substrate stacking step:

FIGS. 15 a-15 c are schematic views respectively explaining oneembodiment of the substrate stacking step. In this embodiment, apositioning alignment is performed by utilizing the opposed substrate 2and the transparent substrate 1 to which a mark for positioning ispreliminarily arranged. In this case, for the purpose of improvingdurability and reliability as the display, an adhesive 32 is arranged ona tip portion of the partition wall 7 as shown in FIG. 15 a, and aconnection between the partition wall 7 and the transparent substrate 1is performed through the adhesive 32. As a method of arranging theadhesive 32, use is made of a method for screen-printing athermo-setting or UV hardening adhesive, a method for arranging anadhesive layer for sealing on an overall surface of the transparentsubstrate 1, or, a method for scattering the liquid powders havingadhesion properties and sealing by heat and pressure.

Further, for the purpose of preventing an inclusion of component, whichaffects the display, such as external moisture content, a sealing agentis applied around an outermost peripheral portion of the substrate so asto seal a space between the substrates. As a method of applying thesealing agent, use is made of a method wherein a sealing agent 34 isapplied to the outermost peripheral portion by means of a sealing agentapplying device 33 as shown in FIG. 15 b after the adhesive 12 isarranged on a tip portion of the partition wall 7 as mentioned above,and then as shown in FIG. 15 c, the transparent substrate 1 and theopposed substrate 2 are positioned by utilizing an position aligningdevice not shown and are stacked.

(4) As to the color filter stacking step:

FIGS. 18 a and 18 b are schematic views respectively explaining oneembodiment of the color filter stacking step. In this embodiment, asshown in FIG. 18 a, a color filter 37 having a plurality of colorregions corresponding to respective cells e.g. having a plurality ofcombinations of R, G, B three fundamental colors is positioned andadhered to the transparent substrate 1 after the substrate stackingstep. Moreover, as shown in FIG. 18 b, in the case that the color filter37 is preliminarily stacked to the transparent substrate 1, it ispossible to obtain the image display panel according to the thirdembodiment having the color filter when the substrate stacking stepexplained in the above (3) is finished. It should be noted that thecolor filter stacking step is necessary in the third embodimentaccording to the invention but is not necessary in the second embodimentwherein the color image display is performed by utilizing no colorfilter.

(5) As to the electrode adhering step:

FIGS. 16 a-16 c are schematic views respectively explaining oneembodiment of the electrode adhering step. In this embodiment, for thepurpose of transmitting a signal for image display to an image displaypanel 35 so as to obtain an image display device wherein the imagedisplay panel 35 (display) is formed as a module, the electrodes 3, 4 ofthe image display plate 35 and a driving circuit 36 are connected. Atfirst, as shown in FIG. 16 a, a stripe electrode with the rib is formedon an outer surface of the transparent substrate I being a front planeas the display electrode 3. Then, as shown in FIG. 16 b, a stripeelectrode with the rib is formed on an outer surface of the opposedsubstrate 2 being a rear plane as the opposed electrode 4. After that,as shown in FIG. 16 c, the electrodes 3, 4 of the image display panel 35and the external driving circuit 36 formed by ACF (AnisotropicConductive Film) are connected, and then the image display device formedas a module is obtained.

As a method of connecting the electrodes, use is made of a method fordirectly installing IC on the substrate by utilizing an adhesive, amethod of installing a flexible printed board by utilizing an adhesiveand so on. As the adhesive, use is made of an anisotropic conductivepaste, and an adhesive in which the conductive particles are notscattered, except for an anisotropic conductive film made of an adhesivehaving an anisotropic property in which the conductive particles arescattered therein as mentioned above.

According to the steps mentioned above, the image display plate 35 isformed as a module, and the image display device is manufactured. FIG.19 is a schematic view showing one embodiment of the color image displayplate 35 manufactured according to the second embodiment of theinvention. In the embodiment shown in FIG. 19, as the liquid powders,use is made of the black liquid powders 5, red liquid powders 6R, greenliquid powders 6G and blue liquid powders 6B. FIGS. 20 a and 20 b areschematic views respectively showing one embodiment of the color imagedisplay plate 35 manufactured according to the third embodiment of theinvention. In the embodiments shown in FIG. 20 a and 29 b, as the liquidpowders, use is made of the black liquid powders 5 and: the white liquidpowders 6, and the color filter 37 having red region 37R, green region37G and blue region 37B is used. In FIG. 20 a, the color filter 37 isarranged lately to the transparent substrate 1, and, in FIG. 20 b, thecolor filter 37 is arranged preliminarily to the transparent substrate1.

In the embodiment mentioned above, the display electrode 3 and theopposed electrode 4 are respectively arranged on outer surfaces of theintegrated image display panel 35. However, as shown in FIGS. 4 and 5,it is possible to arrange the display electrode 3 and the opposedelectrode 4 to inner portions of the image display panel 35. In thiscase, prior to integrate the image display panel 35, the displayelectrode 3 and the opposed electrode 4 may be arranged, Moreover, thepartition walls 7 are arranged only to the opposed substrate 2. However,they are arranged to both of the transparent substrate 1 and the opposedsubstrate 2 and the image display panel 35 is integrated by connectingthe partition walls with each other.

As to the Other Construction Members According to the Invention

Firstly, the substrate will be explained.

In the present invention, at least one of the substrates 1 and 2 is thetransparent substrate through which a color of the liquid powders or theparticles can be observed from outside of the device, and it ispreferred to use a material having a high transmission factor of visiblelight and an excellent heat resistance. Whether a flexibility of thesubstrate is necessary or not is suitably selected in accordance withits use. For example, it is preferred to use a material havingflexibility for the use of electronic paper and so on, and it ispreferred to use a material having no flexibility for the use of adisplay of portable device such as mobile phone, PDA, laptop computerand so on.

Examples of the substrate material include polymer sheets such aspolyethylene terephthalate, polyether sulfone, polyethylene,polycarbonate and inorganic sheets such as glass, quartz or so.

The thickness of the substrate is preferably 2 to 5000 μm, morepreferably 5 to 1000 μm. When the thickness is too thin, it becomesdifficult to maintain strength and distance uniformity between thesubstrates, and when the thickness is too thick, vividness and contrastas a display capability degrade, and in particular, flexibility in thecase of using for an electronic paper deteriorates.

In the case of arranging no electrode on the substrate i.e. in the casethat it is not necessary to form the image display device as a module,as the image display panel wherein the liquid powders or the particlesare moved by means of an electric field produced by external electrodes,the particles or the liquid powders charged in a predeterminedcharacteristic and having a color is pulled in or rebounds with respectto the substrate by means of an electric field generated by applying anelectrostatic latent image on an outer surface of the substrate. Then,the particles or the liquid powders aligned in accordance with theelectrostatic latent image is observed from outside of the displaydevice through the transparent substrate. In this case, theelectrostatic latent image mentioned above can be generated for exampleby a method wherein an electrostatic latent image generated in a knownelectro-photography system using an electro-photography photo-conductoris transferred and formed on the substrate of the image display deviceaccording to the invention, or, by a method wherein an electrostaticlatent image is directly formed on the substrate by an ion flow.

In the case of arranging an electrode on the substrate, i.e. in the casethat the image display device is formed as a module, the particles orthe liquid powders charged in a predetermined characteristic and havinga color is pulled in or rebounds with respect to the substrate by meansof an electric field generated on respective electrodes formed on thesubstrate by applying an outer voltage thereto. Then, the particles orthe liquid powders aligned in accordance with the electrode potential isobserved from outside of the display device through the transparentsubstrate.

With respect to the electrode arranged to the transparent substrate, theelectrode is formed of electro-conductive materials, which aretransparent and having pattern formation capability. As suchelectro-conductive materials, indium oxide, metals such as aluminum, orconductive polymer such as polyaniline, polypyrrole and polythiopheneformed by vacuum vapor deposition method, coating method, and so on.Additionally, the thickness of the electrode may be suitable unless theelectro-conductivity is absent or any hindrance exists in opticaltransparency, and it is preferable to be 3 to 1000 nm, more preferableto be 5 to 400 nm. In this case, the applied outer voltage may besuperimposed with a direct current or an alternate current.

A shape of the partition wall is suitably designed in accordance with asize of the particles or the liquid powders to be used for the displayand is not restricted. However, it is preferred to set a width of thepartition wall to 1-100 μm more preferably 1-50 μm and to set a heightof the partition wall to 10-5000 μm more preferably 10-500 μm.

Moreover, as a method of forming the partition wall, use may be made ofa double rib method wherein ribs are formed on the opposed substratesrespectively and they are connected with each other and a single ribmethod wherein a rib is formed on one of the opposed substrates only. Inthe image display device according to the invention, both methods can bepreferably applied.

The display cell formed by the partition walls each made of rib has asquare shape, a triangular shape, a line shape, a circular shape and ahexagon shape, and has au arrangement such as a grid and a honeycomb, asshown in FIG. 12 viewed from a plane surface of the substrate. Theformation method of the partition wall is not particularly restricted,however, a screen-printing method, a sandblast method, aphotolithography method and an additive method. Among them, it ispreferred to use a photolithography method using a resist film.

It is better to minimize a portion (area of frame portion of the displaycell) corresponding to a cross section of the partition walls viewedfrom the display side.

Then, the liquid powders will be explained.

In the present invention, a term “liquid powder” means an intermediatematerial having both of liquid properties and particle properties andexhibiting a self-fluidity without utilizing gas force and liquid force.Preferably, it is a material having an excellent fluidity such thatthere is no repose angle defining a fluidity of powder. For example, aliquid crystal is defined as an intermediate phase between a liquid anda solid, and has a fluidity showing a liquid characteristic and ananisotropy (optical property) showing a solid characteristic (HeibonshaLtd.: encyclopedia). On the other hand, a definition of the particle isa material having a finite mass if it is vanishingly small and receivesan attraction of gravity (Maruzen Co., Ltd.: physics subject-book).Here, even in the particles, there are special states such as gas-solidfluidized body and liquid-solid fluidized body. If a gas is flown from abottom plate to the particles, an upper force is acted with respect tothe particles in response to a gas speed. In this case, the gas-solidfluidized body means a state that is easily fluidized when the upperforce is balanced with the gravity. In the same manner, the liquid-solidfluidized body means a state that is fluidized by a liquid. (HeibonshaLtd.: encyclopedia) In the present invention, it is found that theintermediate material having both of fluid properties and solidproperties and exhibiting a self-fluidity without utilizing gas forceand liquid force can be produced specifically, and this is defined asthe liquid powder.

That is, as is the same as the definition of the liquid crystal(intermediate phase between a liquid and a solid), the liquid powderaccording to the invention is a material showing the intermediate statehaving both of liquid properties and particle properties, which isextremely difficult to receive an influence of the gravity showing theparticle properties mentioned above and indicates a high fluidity. Sucha material can be obtained in an aerosol state i.e. in a dispersionsystem wherein a solid-like or a liquid-like material is floating in arelatively stable manner as a dispersant in: a gas, and thus, in theimage display device according to the invention, a solid material isused as a dispersant.

As the aerosol state, it is preferred that an apparent volume in amaximum floating state is two times or more than that in none floatingstate, more preferably 2.5 times or more than that in none floatingstate, and most preferably three times or more than that in nonefloating state. In this case, an upper limit is not defined, but it ispreferred that an apparent volume is 12 times or smaller than that innone floating state.

If the apparent volume in the maximum floating state is smaller than twotimes, a display controlling becomes, difficult. On the other hand, ifthe apparent volume in the maximum floating state is larger than 12times, a handling inconvenience during a liquid powder filling operationinto the device such as a particle over-scattering occurs. That is, itis measured by filling the liquid powders in a transparent closed vesselthrough which the liquid powders are seen; vibrating or dropping thevessel itself to obtain a maximum floating state; and measuring anapparent volume at that time from outside of the vessel. Specifically,the liquid powder having a volume ⅕ of the vessel is filled as theliquid powder in a polypropylene vessel with a cap having a diameter(inner diameter) of 6 cm and a height of 10 cm (product name I-boy®produced by As-one Co., Ltd.), the vessel is set in the vibrator, and avibration wherein a distance of 6 cm is repeated at a speed of 3reciprocating/sec. is performed for 3 hours. Then, the apparent volumein the maximum floating state is obtained from an apparent volume justafter a vibration stop.

Moreover, in the image display device according to the invention, it ispreferred that a time change of the apparent volume of the liquidpowders satisfies the following formula:V ₁₀ /V ₅>0.8;here, V₅ indicates the apparent volume (cm³) of the liquid powders after5 minutes from the maximum floating state; and V₁₀ indicates theapparent volume (cm³) of the liquid powders after 10 minutes from themaximum floating state. In this case, in the image display deviceaccording to the invention, it is preferred to set the time changeV₁₀/V₅ of the apparent volume of the liquid powders to larger than 0.85,more preferably larger than 0.9, most preferably larger than 0.95. Ifthe time change V₁₀/V₅ is not larger than 0.8, the liquid powders aresubstantially equal to normal particles, and thus it is not possible tomaintain a high speed response and durability according to theinvention.

Moreover, it is preferred that the average particle diameter d(0.5) ofthe particle materials constituting the liquid powders is 0.1-20 μm,more preferably 0.5-15 μm, most preferably 0.9-8 μm. If the averageparticle diameter d(0.5) is less than 0.1 μm, a display controllingbecomes difficult. On the other hand, if the average particle diameterd(0.5) is larger than 20 μm, a display is possible, but opacifying poweris decreased and thus a thin shape device is difficult. Here, theaverage particle diameter d(0.5) of the particle materials constitutingthe liquid powders is equal to d(0.5) in the following particle diameterdistribution Span.

It is preferred that particle diameter distribution Span of the particlematerial constituting the liquid powders, which is defined by thefollowing formula, is not more than 5 preferably not more than 3:

Particle diameter distribution: Span=(d(0.9)−d(0.1))/d(0.5); here,d(0.5) means a value of the particle diameter expressed by μm wherein anamount of the particle material constituting the liquid powders havingthe particle diameter larger than this value is 50% and an amount of theparticle material constituting the liquid powders having the particlediameter expressed by μm wherein an amount of the particle materialconstituting the liquid powders having a particle diameter smaller thanthis value is 10%, and d(0.9) means a value of the particle diameterexpressed by μm wherein an amount of the particle material constitutingthe liquid powders having the particle diameter smaller than this valueis 90%. If the particle diameter distribution Span of the particlematerials constituting the liquid powders is set to not more than 5,the, particle diameter becomes even and it is possible to perform aneven liquid powder movement.

Here, the particle diameter distribution and the particle diametermentioned above can be measured by means of a laserdiffraction/scattering method. When a laser light is incident upon theparticles to be measured, a light intensity distribution pattern due toa diffraction/scattering light occurs spatially. This light intensitydistribution pattern corresponds to the particle diameter, and thus itis possible to measure the particle diameter and the particle diameterdistribution. In the present invention, it is defined that the particlediameter and the particle diameter distribution are obtained by a volumestandard distribution. Specifically, the particle diameter and theparticle diameter distribution can be measured by means of a measuringapparatus Mastersizer 2000 (Malvern Instruments Ltd.) wherein theparticles setting in a nitrogen gas flow are calculated by an installedanalysis software (which is based on a volume standard distribution dueto Mie's theory).

The liquid powders may be formed by mixing necessary resin, chargecontrol agent, coloring agent, additive and so on and grinding them, or,by polymerizing from monomer, or, by coating a particle with resin,charge control agent, coloring agent, and additive and so on.Hereinafter, typical examples of resin, charge control agent, coloringagent, additive and so on constituting the liquid powders will beexplained.

Typical examples of the resin include urethane resin, acrylic resin,polyester resin, acryl urethane resin, silicone resin, nylon resin,epoxy resin, styrene resin, butyral resin, vinylidene chloride resin,melamine resin, phenolic resin, fluorocarbon polymers, and it ispossible to combine two or more resins. For the purpose of controllingthe attaching force with the substrate, acryl urethane resin, acrylurethane silicone resin, acryl urethane fluorocarbon polymers, urethaneresin, fluorocarbon polymers.

Examples of the electric charge control agent include, positive chargecontrol agent include the fourth grade ammonium salt compound, nigrosinedye, triphenylmethane compound; imidazole derivatives, and so on, andnegative charge control agent such as metal containing azo dye,salicylic acid metal complex, nitroimidazole derivative and so on.

As for a coloring agent, various kinds of basic or acidic dye may beemployable. Examples include Nigrosine, Methylene Blue, quinolineyellow, rose bengal and do on.

Examples of the inorganic additives include titanium oxide, Chinesewhite, zinc sulfide, antimonial oxide, calcium carbonate, zinc white,talc, silica, calcium silicate, alumina white, cadmium yellow, cadmiumred, cadmium orange, titanium yellow, iron blue, ultramarine blue,cobalt blue, cobalt green, cobalt violet, ferric oxide, carbon black,copper powder, aluminum powder and so on.

However, if the above materials are only mixed or coated with nocontrivance, the liquid powders exhibiting an aerosol state cannot beobtained. The regular method of forming the liquid powders exhibiting anaerosol state is not defined, but the following method is preferablyused.

At first, inorganic fine particles having an average particle size of20-100 nm preferably 20-80 nm are preferably fixed on a surface ofmaterials constituting the liquid powders. Moreover, it is preferred totreat the inorganic fine particles by a silicone oil. Here, as for theinorganic fine particles, use may be made of silicon dioxide (silica),zinc oxide, aluminum oxide, magnesium oxide, cerium oxide, ferric oxide,copper oxide and so on. In this case, a method of fixing the inorganicfine particles is important. For example, use may be made of hybridizer(NARA Machinery Co., Ltd.) or mechano-fusion (Hosokawa Micron Co., Ltd.), and the liquid powders showing an aerosol state are formed under apredetermined condition (for example processing time).

Here, in order to further improve a repeating durability, it iseffective to control a stability of the resin constituting the liquidpowders, especially, a water absorbing rate and a solvent insolublerate. It is preferred that the water absorbing rate of the resinconstituting the liquid powders sealed between the substrates is notmore than 3 wt % especially not more than 2 wt %. In this case, ameasurement of the water absorbing rate is performed according toASTM-D570 and a measuring condition is 23° C. for 24 hours, As for thesolvent insoluble rate of the resin constituting the liquid powders, itis preferred that a solvent insoluble rate of the liquid powders, whichis defined by the following formula, is not less than 50% morepreferably not less than 70%:solvent insoluble rate (%)=(B/A)×100;(here, A is a weight of the resin before being immersed into the solventand B is a weight after the resin is immersed into good solvent at 25°C. for 24 hours).

If the solvent insoluble rate is less than 50%, a bleed is generated ona surface of the particle material constituting the liquid powders whenmaintaining for a long time. In this case, it affects an adhesion powerwith the liquid powders and prevents a movement of the liquid powders.Therefore, there is a case such that it affects a durability of theimage display. Here, as a solvent (good solvent) for measuring thesolvent insoluble rate, it is preferred to use fluoroplastic such asmethyl ethyl ketone and so on, polyamide resin such as methanol and soon, acrylic urethane resin such as methyl ethyl ketone, toluene and soon, melamine resin such as acetone, isopropanol and so on, siliconeresin such as toluene and so on.

A surface charge density of a particle substance constituting the liquidpowders can be measured as mentioned below. That is, according to ablow-off method, the liquid powders and carrier particles aresufficiently contacted and a saturated charge amount thereof ismeasured, so that a charge amount per a unit weight of the liquidpowders can be measured. Then, a particle diameter and a specificgravity of the particle substance constituting the liquid powders areseparately measured, and the surface charge density of the liquidpowders is calculated by using them.

<Blow-Off Measuring Theory and Method>

In the blow-off method, a mixture of the liquid powders and the carriersare placed into a cylindrical container with nets at both ends, andhigh-pressure gas is blown from the one end to separate the liquidpowders and the carriers, and then only the liquid powders are blown offfrom the mesh of the net. In this occasion, charge amount of reverseblown polarity remains on the carriers with the same charge amount ofthe liquid powders carried away out of the container. Then, all ofelectric flux by this electric charge are collected to Faraday cage, andare charged across a capacitor with this amount. Accordingly, the chargeamount of the particles is determined as Q=CV (C: capacity, V: voltageacross both ends of the capacitor) by measuring potential of both endsof the capacitor.

In the invention, as a blow-off powder charge amount measuringinstrument, TB-200 produced by Toshiba Chemical Co., Ltd. was used,F963-2535 available from Powder TEC Co., Ltd. was employed as the samekind of carriers, and a specific gravity of the particle substanceconstituting the liquid powders was measured by a multi-volume densitymeter H1305 produced by Shimadzu Corporation. Then, the charge densityper unit surface area (unit: μC/m²) was calculated.

As for a filling amount of the liquid powders, it is preferred tocontrol an occupied volume (volume occupied rate) of the liquid powdersto 5-70 vol %, more preferably 10-65 vol %, most preferably 10-55 vol %of a space between the opposed substrates. If the volume occupied rateof the liquid powders is less than 5 vol %, a clear image display is notperformed, and if it exceeds 70 vol %, the liquid powders becomedifficult to move. Here, a space volume means a volume capable offilling the liquid powders obtained by substituting an occupied portionof the partition wall 4 and a seal portion of the device from a spacebetween the opposed substrates 1 and 2.

Further, in the present invention, it is important to control a gas in agap surrounding the liquid powders between the substrates, and asuitable gas control contributes an improvement of display stability.Specifically, it is important to control a humidity of the gap gas tonot more than 60% RH at 25° C., preferably not more than 50% RH, morepreferably not more than 35% RH. The above gap means a gas portionsurrounding the liquid powders obtained by substituting an occupiedportion of the liquid powders 3, an occupied portion of the partitionwall 4 and a seal portion of the device from the space between theopposed substrates 1 and 2 in FIG. 3.

A kind of the gap gas is not limited if it has the humidity mentionedabove, but it is preferred to use dry air, dry nitrogen gas, dry heliumgas, dry carbon dioxide gas, dry methane gas and so on. It is necessaryto seal this gas in the device so as to maintain the humidity mentionedabove. For example, it is important to perform the operations of fillingthe liquid powders and assembling the substrate under an atmospherehaving a predetermined humidity and to apply a seal member and a sealmethod for preventing a humidity inclusion from outside of the device.

Then, the particles used in the invention will be explained.

The particles may be formed by mixing necessary resin, charge controlagent, coloring agent, additive and so on and grinding them, or, bypolymerizing from monomer, or, by coating a particle with resin, chargecontrol agent, coloring agent, and additive and so on.

Hereinafter, typical examples of resin, charge control agent, coloringagent, additive and so on constituting the liquid powders will beexplained.

Typical examples of the resin include urethane resin, acrylic resin,polyester resin, acryl urethane resin, silicone resin, nylon resin,epoxy resin, styrene resin, butyral resin, vinylidene chloride resin,melamine resin, phenolic resin, fluorocarbon polymers, and it ispossible to combine two or more resins. For the purpose of controllingthe attaching force with the substrate, polyester resin, acryl urethaneresin, acryl urethane silicone resin, acryl urethane fluorocarbonpolymers, urethane resin, fluorocarbon polymers.

Examples of the electric charge control agent include, positive chargecontrol agent include the fourth grade ammonium salt compound, nigrosinedye, triphenylmethane compound, imidazole derivatives, and so on, andnegative charge control agent such as metal containing azo dye,salicylic acid metal complex, nitroimidazole derivative and so on.

As for a coloring agent, various kinds of basic or acidic dye may beemployable. Examples include Nigrosine, Methylene Blue, quinolineyellow, rose bengal and do on.

Examples of the inorganic additives include titanium oxide, Chinesewhite, zinc sulfide, antimonial oxide, calcium carbonate, zinc white,talc, silica, calcium silicate, alumina white, cadmium yellow, cadmiumred, cadmium orange, titanium yellow, iron blue, ultramarine blue,cobalt blue, cobalt green, cobalt violet, ferric oxide, carbon black,manganese ferrite black, cobalt ferrite black, copper powder, aluminumpowder and so on.

Here, in order to further improve a repeating durability, it iseffective to control a stability of the resin constituting theparticles, especially, a water absorbing rate and a solvent insolublerate. It is preferred that the water absorbing rate of the resinconstituting the particles sealed between the substrates is not morethan 3 wt % especially not more than 2 wt %. In this case, a measurementof the water absorbing rate is performed according to ASTM-D570 and ameasuring condition is 23° C. for 24 hours.

As for the solvent insoluble rate of the resin constituting theparticles, it is preferred that a solvent insoluble rate of theparticles, which is defined by the following formula, is not less than50% more preferably not less than 70%:solvent insoluble rate (%)=(B/A)×100;(here, A is a weight of the resin before being immersed into the solventand B is a weight after the resin is immersed into good solvent at 25°C. for 24 hours).

If the solvent insoluble rate is less than 50%, a bleed is generated ona surface of the particles when maintaining for a long time. In thiscase, it affects an adhesion power with the particles and prevents amovement of the particles. Therefore, there is a case such that itaffects a durability of the image display.

Here, as a solvent (good solvent) for measuring the solvent insolublerate, it is preferred to use fluoroplastic such as methyl ethyl ketoneand so on, polyamide resin such as methanol and so on, acrylic urethaneresin such as methyl ethyl ketone, toluene and so on, melamine resinsuch as acetone, isopropanol and so on, silicone resin such as tolueneand so on.

Moreover, the particles have a circular shape preferably.

In the present invention, as a particle diameter distribution ofrespective particles, it is preferred that particle diameterdistribution Span of the particles, which is defined by the followingformula, is not more than 5 preferably not more than 3:Span=(d(0.9)−d(0.1))/d(0.5);here, d(0.5) means a value of the particle diameter expressed by μmwherein an amount of the particles the particle diameter larger thanthis value is 50% and an amount of the particles having the particlediameter expressed by μm wherein an amount of the particles having aparticle diameter smaller than this value is 10%, and d(0.9) means avalue of the particle diameter expressed by μm wherein an amount of theparticles having the particle diameter snaller than this value is 90%.

If the particle diameter distribution Span of the particles is set tonot more than 5, the particle diameter becomes even and it is possibleto perform an even particle movement.

Further, it is preferred to set an average particle diameter d(0.5) ofrespective particles in a range of 0.1-50 μm. If it exceeds this range,a clear display is not performed, and, if it is less than this range, amovement of the particles is prevented due to an excessively largeagglutination power between the particles.

Furthermore, as to a relation between the particles, it is necessary tocontrol a ratio of the d(0.5) of particles having the minimum diameterwith respect to the d(0.5) of particles having the maximum diameter tonot more than 50 preferably not more than 10.

Even in the case that the particle diameter distribution Span is made tobe small, the particles having different charge characteristics aremoved in the opposite direction with each other. Therefore, it ispreferred that the particles can be easily moved by making the particlesize even and by making an amount of the particles to an equal amount,so that the above range is obtained.

Here, the particle diameter distribution and the particle diametermentioned above can be measured by means of a laserdiffraction/scattering method. When a laser light is incident upon theparticles to be measured, a light intensity distribution pattern due toa diffraction/scattering light occurs spatially. This light intensitydistribution pattern corresponds to the particle diameter, and thus itis possible to measure the particle diameter and the particle diameterdistribution.

In the present invention, it is defined that the particle diameter andthe particle diameter distribution are obtained by a volume standarddistribution. Specifically, the particle diameter and the particlediameter distribution can be measured by means of a measuring apparatusMastersizer 2000 (Malvern Instruments Ltd.) wherein the particlessetting in a nitrogen gas flow are calculated by an installed analysissoftware (which is based on a volume standard distribution due to Mie'stheory).

A surface charge density of the particles can be measured as mentionedbelow. That is, according to a blow-off method, the particles andcarrier particles are sufficiently contacted and a saturated chargeamount thereof is measured, so that a charge amount per a unit weight ofthe liquid powders can be measured. Then, a particle diameter and aspecific gravity of the particles are separately measured, and thesurface charge density of the particles is calculated by using them.

In the invention, as a blow-off powder charge amount measuringinstrument, TB-200 produced by Toshiba Chemical Co., Ltd. was used,F963-2535 available from Powder TEC Co., Ltd. was employed as the samekind of carriers, and a specific gravity of the particles was measuredby a multi-volume density meter H1305 produced by Shimadzu Corporation.Then, the charge density per unit surface area (unit: μC/m²) wascalculated.

As for a filling amount of the particles, it is preferred to control anoccupied volume (volume occupied rate) of the particles to 5-70 vol %,more preferably 10-65 vol %, most preferably 10-55 vol % of a spacebetween the opposed substrates. If the volume occupied rate of theparticles is less than 5 vol %, a clear image display is not performed,and if it exceeds 70 vol %, the particles become difficult to move.Here, a space volume means a volume capable of filling the particlesobtained by substituting an occupied portion of the partition wall 4 anda seal portion of the device from a space between the opposed substrates1 and 2.

Further, in the present invention, it is important to control a gas in agap surrounding the particles between the substrates, and a suitable gascontrol contributes an improvement of display stability. Specifically,it is important to control a humidity of the gap gas to not more than60% RH at 25° C., preferably not more than 50% RH, more preferably notmore than 35% RH. The above gap means a gas portion surrounding theparticles obtained by substituting an occupied portion of the particles3, an occupied portion of the partition wall 4 and a seal portion of thedevice from the space between the opposed substrates 1 and 2 in FIG. 3.

A kind of the gap gas is not limited if it has the humidity mentionedabove, but it is preferred to use dry air, dry nitrogen gas, dry heliumgas, dry carbon dioxide gas, dry methane gas and so on.

It is necessary to seal this gas in the device so as to maintain thehumidity mentioned above. For example, it is important to perform theoperations of filling the particles and assembling the substrate underan atmosphere having a predetermined humidity and to apply a seal memberand a seal method for preventing a humidity inclusion from outside ofthe device.

The image display device according to the invention is applicable to theimage display unit for mobile equipment such as notebook personalcomputers, PDAs, cellular phones and so on; to the electric paper forelectric book, electric newspaper and so on; to the bulletin boards suchas signboards, posters, blackboards and so on; to the image display unitfor electric calculator, home electric application products, autosupplies and so on; to the card display unit for point card, IC card andso on; and to the display unit for electric POP, electric advertisement,electric price tag, electric musical score, RF-ID device and so on.

Then, the method of manufacturing the image display panel according tothe invention will be explained in detail with reference to examplesaccording to the invention and comparative examples. However, thepresent invention is not limited to the examples mentioned below.

At first, the examples and the comparative examples of the liquidpowders in the method of manufacturing the image display panel accordingto the invention will be explained.

EXAMPLE 1 Liquid Powders

The image display panel was manufactured as follows.

At first, a substrate (7cm×7cm) with an electrode was prepared, and onthe substrate, a rib having a height of 400 μm was produced to form apartition wall having a stripe shape.

The production of the rib was performed as follows. As an inorganicpowder, a glass powder was prepared by melting, cooling and grinding amixture of SiO₂, Al₂O₃, Bi₂O₃, Bi₂O₃, and ZnO. As a resin, epoxy resinhaving a heat hardening property was prepared. Then, the glass powderand the epoxy resin were mixed with a solvent and controlled to be aviscosity of 12000 cps, so that a paste was produced. Then, the pastewas applied on the substrate and heated at 150° C. to be hardened. Byrepeating the above paste applying and heating steps, a thickness(corresponding to a height of the partition wall) was controlled to be400 μm. Then, a dry photo-resist was adhered. With respect to theadhered dry photo-resist, an exposing step and an etching step wereperformed so as to form a mask by which a partition wall pattern havinga line of 50 μm, a space of 400 μm and a pitch of 250 μm can be formed.Then, unnecessary portions were removed by a sandblast to form apredetermined partition wall having a stripe shape. In this manner, acell between the partition walls was formed on the substrate.

Then, two kinds of the liquid powders (liquid powders X, liquid powdersY) were prepared.

The liquid powders X were produced as follows. At first, methylmethacrylate monomer, TiO₂ (20 phr), charge control agent bontron E89(Orient Chemical Industries, Ltd. 5 phr), initiator AIBN (0.5 phr) weresuspended and polymerized. After that, particle diameters of thepolymerized particles were graded by using a grading device. Then, byusing hybridizer (Nara Machinery Co., Ltd.), the polymerized particles,external additive A (silica H2000, Wacker Ltd.) and external additive B(silica SS20, Japan Silica Ltd.) were set therein and treated at 4800rpm for 5 minuets, so that the external additives were fixed on asurface of the polymerized particles to obtain the liquid powders.

The liquid powders Y were produced as follows. At first, styrenemonomer, azo compounds (5 phr), charge control agent bontron N07 (OrientChemical Industries, Ltd.: 5 phr), initiator AIBN (0.5 phr) weresuspended and polymerized. After that, particle sizes of the polymerizedparticles were graded by using a grading device. Then, by usinghybridizer (Nara Machinery Co., Ltd.), the polymerized particles,external additive C (silica H2050, Wacker Ltd.) and external additive B(silica SS20, Japan Silica Ltd.) were set therein and treated at 4800rpm for 5 minuets, so that the external additives were fixed on asurface of the polymerized particles to obtain the liquid powders.

An average particle diameter of the particles constituting the liquidpowders X was 3.3 μm and a surface charge density thereof was +23 μC/m².An average particle diameter of the particles constituting the liquidpowders Y was 3.1 μm and a surface charge density thereof was −26 μC/m².

Then, according to the method of manufacturing the image display panelaccording to the invention shown in FIG. 10, the liquid powders Xutilized as the first liquid powders 5 were dispersed in a gas from thenozzle 12 provided at the upper portion in the container 11 and werescattered in the cell 9 on the substrate 1 provided at the lower portionin the container 11, so that the liquid powders X were filled in thecell 9. Then, the liquid powders Y utilized as the second liquid powders6 were dispersed in a gas from the nozzle 12 provided at the upperportion in the container 11 and were scattered in the cell 9, in whichthe liquid powders X were preliminarily filled, on the substrate 1provided at the lower portion in the container 11, so that the liquidpowders Y were filled in the cell 9, in which the liquid powders X werepreliminarily filled. In this case, the liquid powders X and the liquidpowders Y were mixed at the same weight with each other, and a fillingrate (volume occupying rate) of the overall liquid powders between theglass substrates was controlled to be 25 vol %.

Then, as shown in FIG. 8, the liquid powders X and Y remaining on thetop of the partition wall 7 were removed by rolling the removing roller21 made of urethane rubber having a diameter of 30 mm (outer peripherallength: 9.4 cm), which was grounded, on the substrate 1. The removingroller 21 made of urethane rubber had JIS-A hardness of 70°. Moreover, avolume specific resistance of urethane rubber used in the removingroller 21, which was measured according to the method shown in FIG. 21,was 6.5×10⁸ Ω·cm. In FIG. 21, numeral 41 was a conductive metal plate(upper plate), numeral 42 was a sample to be measured (here, urethanerubber), numeral 43 was a conductive metal plate (bottom plate), andnumeral 44 was a voltage applying/resistance measuring device.

Then, a glass substrate, to which indium oxide electrode having athickness of about 500 Å was arranged, was stacked to the substratewherein the liquid powders X and the liquid powders Y were filled in thecell. In this case, the peripheral portion of the substrates wasconnected by using an epoxy adhesive, so that the display device wasmanufactured. Moreover, as the gas filled in the space between thesubstrates, use was made of an air having a relative humidity of 35% RH.

EXAMPLE 2 Liquid Powders

The image display panel was manufactured in the same manner as that ofexample 1 except that the rib formation method was different asmentioned below.

The production of the rib was performed as follows. At first, asubstrate (7 cm×7 cm□) with an electrode was prepared, and on thesubstrate, a rib having a height of 50 μm was produced to form apartition wall having a stripe shape. In this case, a photo-sensitivefilm i.e. a dry film photo-resist NIT 250 (Nichigo-Morton Co., Ltd.) waslaminated on a glass with ITO, and the laminated member was subjected toexposure and development, so that the partition wall having desiredline. 30 μm, space: 320 μm and pitch: 350 μm was formed.

COMPARATIVE EXAMPLE 1 Liquid Powders

The same amounts of the liquid powders X and the liquid powders Y werefilled alternately in order in the cell in such a manner that a totalvolume occupying rate became 25 vol %. After that, as shown in FIG. 8,the liquid powders X and Y remaining on the top of the partition wall 7were tried to remove by rolling the removing roller 21 made of urethanerubber including no conductive agents and having a diameter of 30 mm(outer peripheral length: 9.4 mm), which was grounded, on the substrate1. However, not only the liquid powders remaining on the top of thepartition wall but also the liquid powders filled in the cell 9 wereremoved, and the display panel could not be manufactured.

COMPARATIVE EXAMPLE 2 Liquid Powders

The same amounts of the liquid powders X and the liquid powders Y werefilled alternately in order in the cell in such a manner that a totalvolume occupying rate became 25 vol %. After that, as shown in FIG. 8,the liquid powders X and Y remaining on the top of the partition wall 7were tried to remove by rolling the removing roller 21 made of urethanerubber in such a manner that JIS-A hardness became about 30° and havinga diameter of 30 mm (outer peripheral length: 9.4 mm), which wasgrounded, on the substrate 1. However, not only the liquid powdersremaining on the top of the partition wall but also the liquid powdersfilled in the cell 9 were removed, and the display panel could not bemanufactured. The removing roller 21 made of urethane rubber had JIS-Ahardness of 32°. Moreover, a volume specific resistance of urethanerubber used in the removing roller 21, which was measured according tothe method shown in FIG. 21, was 6.3×10⁸ ∩·cm.

COMPARATIVE EXAMPLE 3 Liquid Powders

The same amounts of the liquid powders X and the liquid powders Y werefilled alternately in order in the cell in such a manner that a totalvolume occupying rate became 25 vol %. After that, as shown in FIG. 8,the liquid powders X and Y remaining on the top of the partition wall 7were tried to remove by rolling the removing roller 21 made of urethanerubber in such a manner that JIS-A hardness became about 100° and havinga diameter of 30 mm (outer peripheral length: 9.4 mm), which wasgrounded, on the substrate 1. However, the liquid powders remaining onthe top of the partition wall could not be removed, and the displaypanel could not be manufactured. The removing roller 21 made of urethanerubber had JIS-A hardness of 98°. Moreover, a volume specific resistanceof urethane rubber used in the removing roller 21, which was measuredaccording to the method shown in FIG. 21, was 5.7×10⁸ Ω·cm.

COMPARATIVE EXAMPLE 4 Liquid Powders

By using the same removing roller 21 as that of example 1, as shown inFIG. 9, the roller 21, which was not grounded, was rolled on thesubstrate 1, and the liquid powders X and Y remaining on the top of thepartition wall 7 were tried to remove. However, the liquid powders X andY filled in the cell 9 were also removed, and the display panel was notmanufactured.

With respect to the image display devices installing the image displaypanels manufactured according to the examples 1-2 and the comparativeexamples 1-4, the following evaluations were performed. The results ofthe evaluations were shown in the following Table 1.

“JIS-A hardness of the removing roller”

It was obtained in such a manner that a type A durometer (KOBUNSHI KEIKICO., LTD.) was installed in a constant force apparatus of 1 kgf and avalue was measured after 20 minutes from a pressure plane contact.

“Volume specific resistance of the removing roller”

As shown in FIG. 21, the sheet 42 for the roller material having athickness of 1 cm was arranged between the metal plates 41 and 43, andthe volume specific resistance (Ω·cm) was measured from an electricresistance value when applying a voltage of 500 V.

TABLE 1 Solid state properties of Comparative Comparative ComparativeComparative liquid powder removing roller Example 1 Example 2 Example 1Example 2 Example 3 Example 4 JIS-A hardness (°) 70 70 68 32 98 70Volume specific resistance 6.5 × 10⁸ 6.5 × 10¹³ 8.3 × 10¹³ 6.3 × 10⁸ 5.7× 10⁸ 6.5 × 10⁸ (Ω · cm) Earth grounded grounded grounded groundedgrounded not grounded Unnecessary liquid powder ◯ ◯ X X X X removingstate on partition wall as to unnecessary liquid power removing state onpartition wall ◯: it is possible to favorably remove unnecessary liquidpowers X: it is not possible to favorably remove unnecessary liquidpowers

Then, the examples and the comparative examples of the particles in themethod of manufacturing the image display panel according to theinvention will be explained.

EXAMPLE 3 Particles

The image display panel was manufactured as follows.

At first, a substrate (7 cm×7 cm ) with an electrode was prepared, andon the substrate, a rib having a height of 400 μm was produced to form apartition wall having a stripe shape.

The production of the rib was performed as follows. As an inorganicpowder, a glass powder was prepared by melting, cooling and grinding amixture of SiO₂, Al₂O₃, B₂O₃, Bi₂O₃, and ZnO. As a resin, epoxy resinhaving a heat hardening property was prepared. Then, the glass powderand the epoxy resin were mixed with a solvent and controlled to be aviscosity of 12000 cps, so that a paste was produced. Then, the pastewas applied on the substrate and heated at 150° C. to be hardened. Byrepeating the above paste applying and heating steps, a thickness(corresponding to a height of the partition wall) was controlled to be400 μm. Then, a dry photo-resist was adhered. With respect to theadhered dry photo-resist, an exposing step and an etching step wereperformed so as to form a mask by which a partition wall pattern havinga line of 50 μm, a space of 400 μm and a pitch of 250 μm can be formed.Then, unnecessary portions were removed by a sandblast to form apredetermined partition wall having a stripe shape. In this manner, acell between the partition walls was formed on the substrate.

Then, two kinds of the particles (particles A, particles B) wereprepared.

The particles A (black color particles) were produced in such a mannerthat acrylic urethane resin: EAU53B (Asia Industry Co., Ltd.)/IPDIcross-linking agent: Excel-Hardener HX (Asia Industry Co., Ltd.), CB(Carbon Black) 4 phr, charge control agent: BontronN07 (Orient ChemicalIndustries Ltd.) 2 phr were added, mixed, ground and classified by ajet-mill.

The particles B (white color particles) were produced in such a mannerthat acrylic urethane resin: EAU53B (Asia Industry Co., Ltd.)/IPDIcross-linking agent: Excel-Hardener HX (Asia Industry Co., Ltd.),titanium oxide 10 phr, charge control agent: BontronE89 (Asia IndustryCo., Ltd.) 2 phr were added, mixed, ground and classified by thejet-mill.

An average particle diameter of the particles A was 9.2 μm and anaverage particle diameter of the particles B was 7.1 μm. A surfacecharge density of the particles A was +25 μC/m². Moreover, a surfacecharge density of the particles B was −25 μC/m².

Then, according to the method of manufacturing the image display panelaccording to the invention shown in FIG. 10, the particles A utilized asthe first particles 5 were dispersed in a gas from the nozzle 12provided at the upper portion in the container 11 and were scattered inthe cell 9 on the substrate 1 provided at the lower portion in thecontainer 11, so that the particles A were filled in the cell 9. Then,the particles B utilized as the second powders 6 were dispersed in a gasfrom the nozzle 12 provided at the upper portion in the container 11 andwere scattered in the cell 9, in which the particles A werepreliminarily filled, on the substrate 1 provided at the lower portionin the container 11, so that the particles B were filled in the cell 9,in which the particles A were preliminarily filled. In this case, theparticles A and the particles B were mixed at the same weight with eachother, and a filling rate (volume occupying rate) of the overallparticles between the glass substrates was controlled to be 25 vol %.

Then, as shown in FIG. 8, the particles A and B remaining on the top ofthe partition wall 7 were removed by rolling the removing roller 21 madeof urethane rubber having a diameter of 30 mm (outer peripheral length:9.4 cm), which was grounded, on the substrate 1. The removing roller 21made of urethane rubber had JIS-A hardness of 70°. Moreover, a volumespecific resistance of urethane rubber used in the removing roller 21,which was measured according to the method shown in FIG. 21, was 6.5×10⁸Ω·cm. In FIG. 21, numeral 41 was a conductive metal plate (upper plate),numeral 42 was a sample to be measured (here, urethane rubber), numeral43 was a conductive metal plate (bottom plate), and numeral 44 was avoltage applying/resistance measuring device.

Then, a glass substrate, to which indium oxide electrode having athickness of about 500 Å was arranged, was stacked to the substratewherein the particles A and the particles B were filled in the cell. Inthis case, the peripheral portion of the substrates was connected byusing an epoxy adhesive, so that the display device was manufactured.Moreover, as the gas filled in the space between the substrates, use wasmade of an air having a relative humidity of 35% RH.

EXAMPLE 4 Particles

The image display panel was manufactured in the same manner as that ofexample 3 except that the rib formation method was different asmentioned below.

The production of the rib was performed as follows. At first, asubstrate (7 cm×7 cm□) with an electrode was prepared, and on thesubstrate, a rib having a height of 50 μm was produced to form apartition wall having a stripe shape. In this case, a photo-sensitivefilm i.e. a dry film photo-resist NIT 250 (Nichigo-Morton Co., Ltd.) waslaminated on a glass with ITO, and the laminated member was subjected toexposure and development, so that the partition wall having desiredline: 30 μm, space: 320 μm and pitch: 350 μm was formed.

COMPARATIVE EXAMPLE 5 Particles

The same amounts of the particles A and the particles B were filledalternately in order in the cell in such a manner that a total volumeoccupying rate became 25 vol %. After that, as shown in FIG. 8, theparticles A and B remaining on the top of the partition wall 7 weretried to remove by rolling the removing roller 21 made of urethanerubber including no conductive agents and having a diameter of 30 mm(outer peripheral length: 9.4 mm), which was grounded, on the substrate1. However, not only the particles remaining on the top of the partitionwall but also the particles filled in the cell 9 were removed, and thedisplay panel could not be manufactured. The removing roller 21 made ofurethane rubber had JIS-A hardness of 68°. Moreover, a volume specificresistance of urethane rubber used in the removing roller 21, which wasmeasured according to the method shown in FIG. 21, was 8.3×10¹³ Ω·cm.

COMPARATIVE EXAMPLE 6 Particles

The same amounts of the particles A and the particles B were filledalternately in order in the cell in such a manner that a total volumeoccupying rate became 25 vol %. After that, as shown in FIG. 8, theparticles A and B remaining on the top of the partition wall 7 weretried to remove by rolling the removing roller 21 made of urethanerubber in such a manner that JIS-A hardness became about 30° and havinga diameter of 30 mm (outer peripheral length. 9.4 mm), which wasgrounded, on the substrate 1. However, not only the particles remainingon the top of the partition wall but also the particles filled in thecell 9 were removed, and the display panel could not be manufactured.The removing roller 21 made of urethane rubber had JIS-A hardness of32°. Moreover, a volume specific resistance of urethane rubber used inthe removing roller 21, which was measured according to the method shownin FIG. 21, was 6.3×10⁸ Ω·cm.

COMPARATIVE EXAMPLE 7 Particles

The same amounts of the particles A and the particles B were filledalternately in order in the cell in such a manner that a total volumeoccupying rate became 25 vol %. After that, as shown in FIG. 8, theparticles A and B remaining on the top of the partition wall 7 weretried to remove by rolling the removing roller 21 made of urethanerubber in such a manner that JIS-A hardness became about 100° and havinga diameter of 30 mm (outer peripheral length: 9.4 mm), which wasgrounded, on the substrate 1. However, the particles remaining on thetop of the partition wall could not be removed, and the display panelcould not be manufactured. The removing roller 21 made of urethanerubber had JIS-A hardness of 98°. Moreover, a volume specific resistanceof urethane rubber used in the removing roller 21, which was measuredaccording to the method shown in FIG. 21, was 5.7×10⁸ Ω·cm.

COMPARATIVE EXAMPLE 8 Particles

By using the same removing roller 21 as that of example 1, as shown inFIG. 9, the roller 21, which was not grounded, was rolled on thesubstrate 1, and the particles A and B remaining on the top of thepartition wall 7 were tried to remove. However, the particles A and Bfilled in the cell 9 were also removed, and the display panel was notmanufactured.

With respect to the image display devices installing the image displaypanels manufactured according to the examples 3-4 and the comparativeexamples 5-8, the following evaluations were performed. The results ofthe evaluations were shown in the following Table 2.

“JIS-A hardness of the removing roller”

It was obtained in such a manner that a type A durometer (KOBUNSHI KEIKICO., LTD.) was installed in a constant force apparatus of 1 kgf and avalue was measured after 20 minutes from a pressure plane contact.

“Volume specific resistance of the removing roller”

As shown in FIG. 21, the sheet 42 for the roller material having athickness of 1 cm was arranged between the metal plates 41 and 43, andthe volume specific resistance (Ω·cm) was measured from an electricresistance value when applying a voltage of 500 V.

TABLE 2 Solid state properties of Comparative Comparative ComparativeComparative particle removing roller Example 3 Example 4 Example 5Example 6 Example 7 Example 8 JIS-A hardness (°) 70 70 68 32 98 70Volume specific resistance 6.5 × 10⁸ 6.5 × 10⁸ 8.3 × 10¹³ 6.3 × 10⁸ 5.7× 10⁸ 6.5 × 10⁸ (Ω · cm) Earth grounded grounded grounded groundedgrounded not grounded Unnecessary particle removing ◯ ◯ X X X X state onpartition wall as to unnecessary particle removing state on partitionwall ◯: it is possible to favorably remove unnecessary particles X: itis not possible to favorably remove unnecessary particles

INDUSTRIALLY APPLICABILITY

In the method of manufacturing the image display panel and the imagedisplay device according to the invention, since the method comprises,in the case of filling and setting the liquid powders and the particlesin a plurality of cells formed by the partition walls on the substrate,the steps of: setting a nozzle at an upper portion of a container;setting the substrate, on which the partition walls are arranged, at alower portion of the container; scattering the liquid powders or theparticles dispersed in a gas from the nozzle arranged at the upperportion in the container; and filling the liquid powders or theparticles in the cells on the substrate arranged at the lower portion inthe container, it is possible to seal the liquid powders or theparticles equally and uniformly in a plurality of cells.

Moreover, in the method of manufacturing the image display device andthe image display device according to the invention, since, in the caseof manufacturing the image display device which can display a monotoneimage or a color image, the filling step, the removing step, thesubstrate stacking step and the electrode adhering step are combined, itis possible to form a module including a circuit used for displaying theimage.

1. A method of manufacturing an image display device which comprises animage display panel having one or more image display cells isolated fromeach other by partition walls, in which two kinds of liquid powderscomposed of a solid material stably floating as a dispersoid in a gasand exhibiting a high fluidity in an aerosol state, having a pale brightcolor and a deep dark color and having different charge characteristics,or, two kinds of particles having a pale bright color and a deep darkcolor and having different charge characteristics, are sealed between atransparent substrate and an opposed substrate, and, in which the liquidpowders or the particles, to which an electrostatic field produced by apair of electrodes having different potentials is applied, are made tofly and move so as to display a monotone image, wherein the methodcomprises: filling an amount of the liquid powders or the particles inspaces constituting the image display cells isolated by the partitionwalls; removing unnecessary liquid powders or unnecessary particlesremaining on the partition walls in the filling; stacking thetransparent substrate and the opposed substrate via the partition wallsand applying a sealing agent at a peripheral portion of the substrate soas to make an atmosphere between the transparent substrate and theopposed substrate uniform; and connecting a circuit for displaying theimage to the electrode so as to form a module, wherein an apparentvolume in a maximum floating state of the liquid powders is two times ormore than that in non-floating state.
 2. A method of manufacturing animage display device which comprises an image display panel having oneor more image display cells isolated from each other by partition walls,in which two kinds of liquid powders composed of a solid material stablyfloating as a dispersoid in a gas and exhibiting a high fluidity in anaerosol state, having a color other than white color and a black colorand having different charge characteristics, or, two kinds of particleshaving a color other than white color and a black color and havingdifferent charge characteristics, are sealed between a transparentsubstrate and an opposed substrate, and, in which the liquid powders orthe particles, to which an electrostatic field produced by a pair ofelectrodes having different potentials is applied, are made to fly andmove so as to display a color image, wherein the method comprises:filling an amount of the liquid powders or the particles in spacesconstituting the image display cells isolated by the partition walls;removing unnecessary liquid powders or unnecessary particles remainingon the partition walls in the filling; stacking the transparentsubstrate and the opposed substrate via the partition walls and applyinga sealing agent at a peripheral portion of the substrate so as to makean atmosphere between the transparent substrate and the opposedsubstrate uniform; and connecting a circuit for displaying the image tothe electrode so as to form a module; wherein an apparent volume in amaximum floating state of the liquid powders is two times or more thanthat in non-floating state.
 3. A method of manufacturing an imagedisplay device which comprises an image display panel having one or moreimage display cells isolated from each other by partition walls, inwhich two kinds of liquid powders composed of a solid material stablyfloating as a dispersoid in a gas and exhibiting a high fluidity in anaerosol state, having a white color and a black color and havingdifferent charge characteristics, or, two kinds of particles having awhite color and a black color and having different chargecharacteristics, are sealed between a transparent substrate and anopposed substrate, and, in which the liquid powders or the particles, towhich an electrostatic field produced by a pair of electrodes havingdifferent potentials is applied, are made to fly and move so as todisplay a color image via a color filter provided to the transparentsubstrate constituting a front panel, wherein the method comprises:filling an amount of the liquid powders or the particles in spacesconstituting the image display cells isolated by the partition walls;removing unnecessary liquid powders or unnecessary particles remainingon the partition walls in the filling step; stacking the transparentsubstrate and the opposed substrate via the partition walls and applyinga sealing agent at a peripheral portion of the substrate so as to makean atmosphere between the transparent substrate and the opposedsubstrate uniform; and connecting a circuit for displaying the image tothe electrode so as to form a module, wherein an apparent volume in amaximum floating state of the liquid powders is two times or more thanthat in non-floating state.
 4. A method of manufacturing an imagedisplay device which comprises an image display panel having one or moreimage display cells isolated from each other by partition walls, inwhich two kinds of liquid powders composed of a solid material stablyfloating as a dispersoid in a gas and exhibiting a high fluidity in anaerosol state, having a pale bright color and a deep dark color andhaving different charge characteristics, or, two kinds of particleshaving a pale bright color and a deep dark color and having differentcharge characteristics, are sealed between a transparent substrate andan opposed substrate, and, in which the liquid powders or the particles,to which an electrostatic field produced by a pair of electrodes havingdifferent potentials is applied, are made to fly and move so as todisplay a monotone image, wherein the method comprises: filling anamount of the liquid powders or the particles in spaces constituting theimage display cells isolated by the partition walls; removingunnecessary liquid powders or unnecessary particles remaining on thepartition walls in the filling; stacking the transparent substrate andthe opposed substrate via the partition walls and applying a sealingagent at a peripheral portion of the substrate so as to make anatmosphere between the transparent substrate and the opposed substrateuniform; and connecting a circuit for displaying the image to theelectrode so as to form a module wherein a time change of an apparentvolume of the liquid powders satisfies the following formula:V ₁₀/V ₅>0.8; wherein, V₅ indicates the apparent volume (cm₃) of theliquid powders after 5 minutes from the maximum floating state; and V₁₀indicates the apparent volume (cm₃) of the liquid powders after 10minutes from the maximum floating state.
 5. A method of manufacturing animage display device which comprises an image display panel having oneor more image display cells isolated from each other by partition walls,in which two kinds of liquid powders composed of a solid material stablyfloating as a dispersoid in a gas and exhibiting a high fluidity in anaerosol state, having a pale bright color and a deep dark color andhaving different charge characteristics, or, two kinds of particleshaving a pale bright color and a deep dark color and having differentcharge characteristics, are sealed between a transparent substrate andan opposed substrate, and, in which the liquid powders or the particles,to which an electrostatic field produced by a pair of electrodes havingdifferent potentials is applied, are made to fly and move so as todisplay a monotone image, wherein the method comprises: filling anamount of the liquid powders or the particles in spaces constituting theimage display cells isolated by the partition walls; removingunnecessary liquid powders or unnecessary particles remaining on thepartition walls in the filling; stacking the transparent substrate andthe opposed substrate via the partition walls and applying a sealingagent at a peripheral portion of the substrate so as to make anatmosphere between the transparent substrate and the opposed substrateuniform; and connecting a circuit for displaying the image to theelectrode so as to form a module wherein an average particle diameterd(0.5) of a particle component constituting the liquid powders is 0.1 -20 μm.
 6. A method of manufacturing an image display device whichcomprises an image display panel having one or more image display cellsisolated from each other by partition walls, in which two kinds ofliquid powders composed of a solid material stably floating as adispersoid in a gas and exhibiting a high fluidity in an aerosol state,having a pale bright color and a deep dark color and having differentcharge characteristics, or, two kinds of particles having a pale brightcolor and a deep dark color and having different charge characteristics,are sealed between a transparent substrate and an opposed substrate,and, in which the liquid powders or the particles, to which anelectrostatic field produced by a pair of electrodes having differentpotentials is applied, are made to fly and move so as to display amonotone image, wherein the method comprises: filling an amount of theliquid powders or the particles in spaces constituting the image displaycells isolated by the partition walls; removing unnecessary liquidpowders or unnecessary particles remaining on the partition walls in thefilling; stacking the transparent substrate and the opposed substratevia the partition walls and applying a sealing agent at a peripheralportion of the substrate so as to make an atmosphere between thetransparent substrate and the opposed substrate uniform; and connectinga circuit for displaying the image to the electrode so as to form amodule wherein a difference between surface charge densities of the twokinds of particles measured by utilizing same carrier and in accordancewith a blow-off method is 5 μC/m² -150 μC/m² in an absolute value.
 7. Amethod of manufacturing an image display device which comprises an imagedisplay panel having one or more image display cells isolated from eachother by partition walls, in which two kinds of liquid powders composedof a solid material stably floating as a dispersoid in a gas andexhibiting a high fluidity in an aerosol state, having a pale brightcolor and a deep dark color and having different charge characteristics,or, two kinds of particles having a pale bright color and a deep darkcolor and having different charge characteristics, are sealed between atransparent substrate and an opposed substrate, and, in which the liquidpowders or the particles, to which an electrostatic field produced by apair of electrodes having different potentials is applied, are made tofly and move so as to display a monotone image, wherein the methodcomprises: filling an amount of the liquid powders or the particles inspaces constituting the image display cells isolated by the partitionwalls; removing unnecessary liquid powders or unnecessary particlesremaining on the partition walls in the filling; stacking thetransparent substrate and the opposed substrate via the partition wallsand applying a sealing agent at a peripheral portion of the substrate soas to make an atmosphere between the transparent substrate and theopposed substrate uniform; and connecting a circuit for displaying theimage to the electrode so as to form a module wherein the particles areparticles in which the maximum surface potential, in the case that thesurface of particles is charged by a generation of Corona dischargecaused by applying a voltage of 8 KY to a Corona discharge devicedeployed at a distance of 1 mm from the surface, is 300 V or greater at0.3 second after the discharge.
 8. A method of manufacturing an imagedisplay device which comprises an image display panel having one or moreimage display cells isolated from each other by partition walls, inwhich two kinds of liquid powders composed of a solid material stablyfloating as a dispersoid in a gas and exhibiting a high fluidity in anaerosol state, having a color other than white color and a black colorand having different charge characteristics, or, two kinds of particleshaving a color other than white color and a black color and havingdifferent charge characteristics, are sealed between a transparentsubstrate and an opposed substrate, and, in which the liquid powders orthe particles, to which an electrostatic field produced by a pair ofelectrodes having different potentials is applied, are made to fly andmove so as to display a color image, wherein the method comprises:filling an amount of the liquid powders or the particles in spacesconstituting the image display cells isolated by the partition walls;removing unnecessary liquid powders or unnecessary particles remainingon the partition walls in the filling; stacking the transparentsubstrate and the opposed substrate via the partition walls and applyinga sealing agent at a peripheral portion of the substrate so as to makean atmosphere between the transparent substrate and the opposedsubstrate uniform; and connecting a circuit for displaying the image tothe electrode so as to form a module wherein a time change of anapparent volume of the liquid powders satisfies the following formula:V ₁₀/V ₅>0.8; wherein, V₅ indicates the apparent volume (cm³) of theliquid powders after 5 minutes from the maximum floating state; and V₁₀indicates the apparent volume (cm³) of the liquid powders after 10minutes from the maximum floating state.
 9. A method of manufacturing animage display device which comprises an image display panel having oneor more image display cells isolated from each other by partition walls,in which two kinds of liquid powders composed of a solid material stablyfloating as a dispersoid in a gas and exhibiting a high fluidity in anaerosol state, having a color other than white color and a black colorand having different charge characteristics, or, two kinds of particleshaving a color other than white color and a black color and havingdifferent charge characteristics, are sealed between a transparentsubstrate and an opposed substrate, and, in which the liquid powders orthe particles, to which an electrostatic field produced by a pair ofelectrodes having different potentials is applied, are made to fly andmove so as to display a color image, wherein the method comprises:filling an amount of the liquid powders or the particles in spacesconstituting the image display cells isolated by the partition walls;removing unnecessary liquid powders or unnecessary particles remainingon the partition walls in the filling; stacking the transparentsubstrate and the opposed substrate via the partition walls and applyinga sealing agent at a peripheral portion of the substrate so as to makean atmosphere between the transparent substrate and the opposedsubstrate uniform; and connecting a circuit for displaying the image tothe electrode so as to form a module wherein an average particlediameter d(0.5) of a particle component constituting the liquid powdersis 0.1 - 20 μm.
 10. A method of manufacturing an image display devicewhich comprises an image display panel having one or more image displaycells isolated from each other by partition walls, in which two kinds ofliquid powders composed of a solid material stably floating as adispersoid in a gas and exhibiting a high fluidity in an aerosol state,having a color other than white color and a black color and havingdifferent charge characteristics, or, two kinds of particles having acolor other than white color and a black color and having differentcharge characteristics, are sealed between a transparent substrate andan opposed substrate, and, in which the liquid powders or the particles,to which an electrostatic field produced by a pair of electrodes havingdifferent potentials is applied, are made to fly and move so as todisplay a color image, wherein the method comprises: filling an amountof the liquid powders or the particles in spaces constituting the imagedisplay cells isolated by the partition walls; removing unnecessaryliquid powders or unnecessary particles remaining on the partition wallsin the filling; stacking the transparent substrate and the opposedsubstrate via the partition walls and applying a sealing agent at aperipheral portion of the substrate so as to make an atmosphere betweenthe transparent substrate and the opposed substrate uniform; andconnecting a circuit for displaying the image to the electrode so as toform a module wherein a difference between surface charge densities ofthe two kinds of particles measured by utilizing same carrier and inaccordance with a blow-off method is 5 μC/m² -150 μC/m² in an absolutevalue.
 11. A method of manufacturing an image display device whichcomprises an image display panel having one or more image display cellsisolated from each other by partition walls, in which two kinds ofliquid powders composed of a solid material stably floating as adispersoid in a gas and exhibiting a high fluidity in an aerosol state,having a color other than white color and a black color and havingdifferent charge characteristics, or, two kinds of particles having acolor other than white color and a black color and having differentcharge characteristics, are sealed between a transparent substrate andan opposed substrate, and, in which the liquid powders or the particles,to which an electrostatic field produced by a pair of electrodes havingdifferent potentials is applied, are made to fly and move so as todisplay a color image, wherein the method comprises: filling an amountof the liquid powders or the particles in spaces constituting the imagedisplay cells isolated by the partition walls; removing unnecessaryliquid powders or unnecessary particles remaining on the partition wallsin the filling; stacking the transparent substrate and the opposedsubstrate via the partition walls and applying a sealing agent at aperipheral portion of the substrate so as to make an atmosphere betweenthe transparent substrate and the opposed substrate uniform; andconnecting a circuit for displaying the image to the electrode so as toform a module wherein the particles are particles in which the maximumsurface potential, in the case that the surface of particles is chargedby a generation of Corona discharge caused by applying a voltage of 8 KYto a Corona discharge device deployed at a distance of 1 mm from thesurface, is 300 V or greater at 0.3 second after the discharge.
 12. Amethod of manufacturing an image display device which comprises an imagedisplay panel having one or more image display cells isolated from eachother by partition walls, in which two kinds of liquid powders composedof a solid material stably floating as a dispersoid in a gas andexhibiting a high fluidity in an aerosol state, having a white color anda black color and having different charge characteristics, or, two kindsof particles having a white color and a black color and having differentcharge characteristics, are sealed between a transparent substrate andan opposed substrate, and, in which the liquid powders or the particles,to which an electrostatic field produced by a pair of electrodes havingdifferent potentials is applied, are made to fly and move so as todisplay a color image via a color filler provided to the transparentsubstrate constituting a front panel, wherein the method comprises:filling an amount of the liquid powders or the particles in spacesconstituting the image display cells isolated by the partition walls;removing unnecessary liquid powders or unnecessary particles remainingon the partition walls in the filling step; stacking the transparentsubstrate and the opposed substrate via the partition walls and applyinga sealing agent at a peripheral portion of the substrate so as to makean atmosphere between the transparent substrate and the opposedsubstrate uniform; and connecting a circuit for displaying the image tothe electrode so as to form a module wherein a time change of anapparent volume of the liquid powders satisfies the following formula:V ₁₀/V 5 >0.8; wherein, V₅ indicates the apparent volume (cm³) of theliquid powders after 5 minutes from the maximum floating state; and V₁₀indicates the apparent volume (cm³) of the liquid powders after 10minutes from the maximum floating state.
 13. A method of manufacturingan image display device which comprises an image display panel havingone or more image display cells isolated from each other by partitionwalls, in which two kinds of liquid powders composed of a solid materialstably floating as a dispersoid in a gas and exhibiting a high fluidityin an aerosol state, having a white color and a black color and havingdifferent charge characteristics, or, two kinds of particles having awhite color and a black color and having different chargecharacteristics, are sealed between a transparent substrate and anopposed substrate, and, in which the liquid powders or the particles, towhich an electrostatic field produced by a pair of electrodes havingdifferent potentials is applied, are made to fly and move so as todisplay a color image via a color filter provided to the transparentsubstrate constituting a front panel, wherein the method comprises:filling an amount of the liquid powders or the particles in spacesconstituting the image display cells isolated by the partition walls;removing unnecessary liquid powders or unnecessary particles remainingon the partition walls in the filling step; stacking the transparentsubstrate and the opposed substrate via the partition walls and applyinga sealing agent at a peripheral portion of the substrate so as to makean atmosphere between the transparent substrate and the opposedsubstrate uniform; and connecting a circuit for displaying the image tothe electrode so as to form a module wherein an average particlediameter d(O.5) of a particle component constituting the liquid powdersis 0.1 - 20 μn.
 14. A method of manufacturing an image display devicewhich comprises an image display panel having one or more image displaycells isolated from each other by partition walls, in which two kinds ofliquid powders composed of a solid material stably floating as adispersoid in a gas and exhibiting a high fluidity in an aerosol state,having a white color and a black color and having different chargecharacteristics, or, two kinds of particles having a white color and ablack color and having different charge characteristics, are sealedbetween a transparent substrate and an opposed substrate, and, in whichthe liquid powders or the particles, to which an electrostatic fieldproduced by a pair of electrodes having different potentials is applied,are made to fly and move so as to display a color image via a colorfilter provided to the transparent substrate constituting a front panel,wherein the method comprises: filling an amount of the liquid powders orthe particles in spaces constituting the image display cells isolated bythe partition walls; removing unnecessary liquid powders or unnecessaryparticles remaining on the partition walls in the filling step; stackingthe transparent substrate and the opposed substrate via the partitionwalls and applying a sealing agent at a peripheral portion of thesubstrate so as to make an atmosphere between the transparent substrateand the opposed substrate uniform; and connecting a circuit fordisplaying the image to the electrode so as to form a module wherein adifference between surface charge densities of the two kinds ofparticles measured by utilizing same carrier and in accordance with ablow-off method is 5 μC/m² -150 μC/m² in an absolute value.
 15. methodof manufacturing an image display device which comprises an imagedisplay panel having one or more image display cells isolated from eachother by partition walls, in which two kinds of liquid powders composedof a solid material stably floating as a dispersoid in a gas andexhibiting a high fluidity in an aerosol state, having a white color anda black color and having different charge characteristics, or, two kindsof particles having a white color and a black color and having differentcharge characteristics, are sealed between a transparent substrate andan opposed substrate, and, in which the liquid powders or the particles,to which an electrostatic field produced by a pair of electrodes havingdifferent potentials is applied, are made to fly and move so as todisplay a color image via a color filter provided to the transparentsubstrate constituting a front panel, wherein the method comprises:filling an amount of the liquid powders or the particles in spacesconstituting the image display cells isolated by the partition walls;removing unnecessary liquid powders or unnecessary particles remainingon the partition walls in the filling step; stacking the transparentsubstrate and the opposed substrate via the partition walls and applyinga sealing agent at a peripheral portion of the substrate so as to makean atmosphere between the transparent substrate and the opposedsubstrate uniform; and connecting a circuit for displaying the image tothe electrode so as to form a module wherein the particles are particlesin which the maximum surface potential, in the case that the surface ofparticles is charged by a generation of Corona discharge caused byapplying a voltage of 8 KY to a Corona discharge device deployed at adistance of 1 mm from the surface, is 300 V or greater at 0.3 secondafter the discharge.